Genuine interest in fine arts

ChessWriter wrote:

This is a question from the Kaplan Live Premier Online program. You can see the official answer as well as the official explanation in the image above.

I am confused between options A and B.

The stimulus says that "this is true DESPITE the oft mentioned record levels of attendance". The word "despite" suggests that the record levels of attendance should somehow suggest that the level of interest in art is increasing, but that in this case it isn't. Option B should be correct because it strengthens this idea.

The official explanation says that option B actually weakens the conclusion! I can't see how this can be right.
Is it possible that Kaplan provided us the wrong answer to this CR problem?

The premise is that there has been a RECORD LEVEL OF ATTENDANCE.
The conclusion is that FEWER PEOPLE HAVE A GENUINE INTEREST IN THE ARTS.

The passage links the RECORD LEVEL ATTENDANCE to FEWER PEOPLE with a genuine interest in the arts.
The correct answer must strengthen this link.

Answer choice A: The increase in the NUMBER OF PEOPLE WHO VISIT MUSEUMS MORE THAN ONCE has been greater than the increase in the NUMBER OF VISITS to these museums.
The implication is that the RECORD LEVEL OF ATTENDANCE has been due to an increase in the number of people who visit the museum MORE THAN ONCE.
In other words, there have been more visits, but FEWER VISITORS -- strengthening the conclusion that fewer people have a genuine interest in the arts.

The correct answer is A.

Answer choice B: An interest in the arts cannot be determined by examining levels of museum attendance.
While the passage links the LEVEL OF ATTENDANCE to a LACK OF INTEREST in the arts, answer choice B states that interest in the arts CANNOT BE DETERMINED by examining museum attendance -- thereby WEAKENING the link that the argument is trying to establish.
Eliminate B.