Why is B correct?

I see where your are coming from here! I agree that as common sense runs, B strictly speaking doesn't have to be true. However, the question asks that if the passage is true, what is true. The passage explicitly says that they can only help patients after the drugs reach the marketplace. I would reconcile this by reading into the passage a definition of patients as the general patient population, rather than those in clinical trials. I think when you come across a premise you disagree with, which I do here, you also just need to get used to that discomfort and accept it for the sake of a must be true. The same muscle that is hugely helpful in strength or weaken questions actually can impede you in must be trues.

How do you avoid the trap answer of C? That seems like such a good answer to choose...