I still don't get how the correct answer choice HAS to be true. how do we know that the costs of cataracts surgery today is decreasing?

can someone explain why B is correct. i still dont get how it is.

Hi, I am still confused on how choice D doesn't weaken the argument? Choice A seems like a weak answer choice doesn't it?

This question doesn't seem like it would be an NA question, it seems more of a SA question due the stem. Is this correct to assume?