PT12.S1.Q24 - Until recently it was thought that ink used

Grace...

I am having trouble understanding why A is the right answer.

P: Ink from Bible by Gutenberg contains titanium. Ink of another bible from 15th Century contains titanium. Ink from other printing from 15th century does not contain titanium. (from the word "another" I am thinking that Gutenberg Bible was from 15th Century)

Conclusion: This finding supports (1) B3 bible was printed by Gutenberg, (2) We cannot doubt that the Vinland Map is not from 15th century because of the presence of titanium in the ink.

In arriving the first conclusion, the author is making an assumption that only Gutenberg used ink containing titanium in 15th century.
What I don't understand it that in arriving second conclusion, I don't see that the author is making an assumption that ink containing titanium was widely used (not restricted as the answer choice A states). I am thinking that it could be that those Vinland Maps were printed by Gutenberg. In that case, the second conclusion follows well. The second conclusion is based on the premise that ink containing titanium was used in 15th century by somebody. How can we say that the author is assuming that titanium ink was widely used (not restricted) from this conclusion? The premise is talking about one Vinland Map in question and we don't know how popular that map was during that time. It could be there were only few copies made by Gutenberg, then can't we conclude that presence of titanium in the ink of Vinland Map is no longer a reason to doubt of 15th century authenticity?

Thank you for any help you can give.

BlindReviewer

Answer choice A is correct because the argument being made is paradoxical. It says now that we found titanium in this one thing made by Gutenberg, we can be support two things: 1) this other thing was made by Gutenberg and 2) this Vinland Map that also has titanium now has more support to show that it came from the fifteenth century.

But if we read this again, how does this make any sense? How can we say that the presence of titanium in this thing made by Gutenberg links it to another thing made by Gutenberg AND shows that everyone used titanium at this time? If we were in our right minds we would also have to say the Vinland Maps were made by Gutenberg as well.

Hopefully that makes sense and perhaps other people have different explanations (I actually got tripped up by this question too haha).