How do you answer a question like that? That's for you to decide. As for me, I do not believe it is. Ask yourself a fundamental question, "Do you believe in the Bible as the unadulterated word of God?" If the answer is yes, then use it as a measuring stick by which to compare church teaching in all religions.
That's up for you to decide. As a catholic, I believe that it is, and this is why:
Most Christians believe that the true church is completely in line with the teachings of the bible. I believe this too, but there is an issue here. These christian churches rely on the personal interpretation of its members to determine the messages of the bible. This is why there are so many denominations, and they can't agree with each other on any matter of doctrinal faith. The misinterpretation of biblical passages because of a lack of knowledge in linguistics, anthropology, traditional Hebrew culture (etc) leads to doctrines which are not truly in line with this 'true Christianity'. This has also lead to a lot of the misinterpretation of catholic practice and beliefs by protestant onlookers.
A lot of protestant beliefs also tend to be contradicted by other passages within the bible, and these disconcerting passages are overlooked. catholic theology does not have the same contradictions, but only if they are interpreted correctly. This is why the catholic people put their faith in the catholic priesthood, who know how the written word is to be interpreted. they did compile the whole book in the first place, after all.
sacred oral tradition in conjunction with sacred scripture form the teaching basis of the catholic church. Sola Scripture, a protestant invention only 400 years old, falls flat on its face when you consider that the infallibility of the bible is not mentioned anywhere in the bible itself, and that the last verse in the gospel of John distinctly says that the bible is not a complete 'stand-alone' guide. Therefore, the infallibility of the bible must come from a church which is infallible, because of the holy spirit. The only two churches which fit the bill are the catholic and orthodox churches.
Therefore, there are really only two candidates for the 'true church'. The others are lacking in one way or another.
I am surprised by the many educated people like to days answerer's, that say the Roman Catholic church and the re-erected Catholic church (The Vatican) have anything to do with the apostle Petrus. The history of cheating this strange claim is very well known. As a matter of fact, ancient documents about their claims were pr oven to be false. Here only remains the important assumption that Petrus was in Rome, where he could have given the job to... really any-one. 1) Petrus was never in Rome and did not die there. The biggest church, the Saint Pieter was build on the Roman Circus where Petrus should have died and should have been buried. People only do so and say so because it would be so important if he was. People will keep telling you this. Paulus mentioned 27 people in Rome by the year 58. Later he was in Rome himself but wrote that all had forsaken him. Where was Petrus the Pope in the story? 2 Timothe?s 4:16. He was absolutely no Pope or important Christian leader there and he was not in Rome. He had been in Babylon, the Catholic church states that this would mean Rome somehow but this remains to be just a weak assumption. Babylon is not Rome. Further the rest, the Catholic faith is quite different, so how could they have known Petrus and have agreed on anything that he said? 2) Petrus was married and he probably liked it when he warned against people who would not allow woman to marry but the popes were not allowed to marry and so were the priest through all times. (1 Timotheus 4:1-3) 3) Peter said the bible was the only true word of God and that we should only pay attention to this, unlike the Catholics with all their traditions. 4) Petrus warned explicitly for people who bargained faith and would sell it, the Catholics always traded with it (prayers, masses and forgiveness of sins for money). 5) Petrus: baptizing not important but a symbol, Catholics: baptizing most important. 6) Petrus did not like to be worshiped but Catholics did like to take that to the max. 7) Petrus: Being saved only through justification of Jesus Christ, Catholics: their sacraments are also needed in order to be saved. 8) Peter had led the church as an equal person and learned us not to do that as a master. The Catholic church works very much with authority and invented many titles along the way. Many of these titles mean Father (Pope Gr. pappas; Lat. papa is an example) and Petrus learned not to call anybody on earth father for only one is our Father, the one in heaven (Matthe?s 23:9). 9) Petrus said there can only be one priesthood, the one from Jesus Christ. Catholics have been needing a priesthood for their sacraments and it is prominent. 10) Petrus: Jesus is the Rock. Catholics: Petrus is the Rock. 11) Petrus: reborn through the word of God. Catholics: reborn through baptism. 12) Petrus: Jesus ones suffered for our sins. Catholics: Going to church for sacraments and the priests is necessary to continue the offering of Jesus. 13) Petrus: you can be sure to go to heaven. Catholics: you only know when you die. 14) Petrus learned that a believer can not be a murderer, thief, some-one evil or someone who is curious for another's affairs, the popes have been all that and it is disgusting what they have done to other Christians.