Does r have exactly four distinct positive factors?

(1) r is the product of two numbers, each of them prime numbers.
(2) r = 57

r could be the product of 2 x 2 because the question doesn't say whether the two prime numbers are distinct or not. When the two numbers are the same r has 3 not 4 factors. (1, 2,4) Therefore the answer must be (B) not (D)

you are absolutely right. In the problem statement it should say that the two prime numbers are different. The problem has been updated. Thank you for your feedback

Steve