Art Historian: Recently, computer analysis has revealed that

Good question.

C is the only correct answer in this stem, because others go too far. Here is my reasons.

Background:Art Historian: Recently, computer analysis has revealed that a few of a famous Flemish artist’s works are forgeries, and are actually the work of noted forger Elmyr de Hory. While such a development may emit violent reverberations through the art world, even those museums that have a wealth of the Flemish artist in their collections should not be overly concerned.

Premise:Hundreds of this Flemish artist’s works were tested to determine whether they were forgeries, yet only a slim few turned out to be actual forgeries.

Conclusion:Thus, the master’s reputation as one of the greatest artists humanity has ever produced will surely remain undiminished.

A. The computer analysis involved is more likely to mistake an actual work as a forgery than to mistake a forgery as an actual work.

This option actually strengthened the conclusion, If the computer analysis works like this, then it will be easy to treat the real masterpieces as fake stuffs, needless to say that the fake stuff will totally be terminated. but in the stem few pictures have been demonstrated as fake stuff. Strengthen the conclusion.

B. Many of the Flemish artist’s well known portraits are in the collection of private owners and were therefore not subjected to computer analysis.

This option is irrelevant. First, it told us nothing about the sample in the test. Second, we don't know whether the pieces in the collection of private owners are authentic or counterfeit, we can't conclude that the more the private owners have, the more authentic the pieces are. In the stem we can't find out this assumption.

C. Some of the works upon which Flemish artist’s standing rests were identified by the computer analysis to be the work of de Hory.

NOTICE:SOME OF,this option is very tricky because it seems like the reversion of the stem, please NOTCIE the quote in the stem,"Hundreds of this Flemish artist’s works were tested to determine whether they were forgeries". We don't know whether there are other pieces, it just hundreds. What if the painter got thousands of works? Maybe the tester unfortunately chose the right one to demonstrate and then make a conclusion. Weaken

D. Some museums, worrying that their most prized painting from the Flemish artist would be deemed forgeries, and thus lose value, only offered up the artist’s lesser known works for computer analysis.

irrelevant. Again, the wrong assumption here is: The greater the works are, the less likely the fake is. We can't simply jump to the conclusion with that assumption to weak the argument because the stem does not tell us this assumption.

E. Though few in the art world dispute the outcome of the computer analysis of the Flemish artist’s work, many contend that the identified forgeries are not the work of Elmyr de Hory but some other highly skilled forger.

irrelevant.. This one is tricky because it introduced some other highly skilled forger. But it didn't attack the conclusion. Even if the forgeries are work of other skilled forger, then what? The data told us that forgeries is FEW, so this option changes nothing of the argument.

Hope it helps.