Inference

[BTGmoderatorRO]

Box office receipts for independent movies for the first half of this year have increased by 20 percent over the total receipts for independent movies for all of last year. Last year, 50 independent movies were released, while so far this year only 20 independent movies have been released. The number of independent movies slated for release in the second half of this year is roughly equal to the number released so far.
If the statements above are true, which of the following must be true?

(A) The total box office receipts for independent movies this year will be significantly more than 20 percent greater than the receipts for independent movies last year.
(B) The number of independent movies released in the first half of this year is equal to the number released in the first half of last year.
(C) The price of a movie ticket has not increased since last year.
(D) The average receipts for the independent films released during the first half of this year is greater than that of all independent films released last year.
(E) The number of people seeing independent movies during the first half of this year is greater than the number who saw independent movies last year.
OA is d

Please what is wrong with option B? Do you have another approach to get the correct answer to this question?
Thanks in anticipation for your response

[EconomistGMATTutor]

This is an inference question, so you must take the evidence given and see what can be absolutely concluded.

The correct choice is D. Since box office receipts are greater this half-year -- with only 20 releases -- than box office receipts last year, with 50 releases, the average receipts must be greater this half-year than last year. Let's say that so far this year, receipts were $10 million. Last year's receipts must be less than that, so let's say $9 million. The average for last year is $10 million divided by the 20 releases. Last year's average is a smaller total ($9 million) divided by a larger number of releases (50). Last year's average must be less.

You asked about Choice B. I would say: why do you think this must be true? The number released in the first half of this year is 20. The number released in the first half of last year is unknown. Could have been 1, 10, 20, 40 . . . Who knows? Remember, you need a choice that must be true given the evidence.

I'm available if you'd like any follow up.