Answer the question before reading the answer choice. For this question, your answer will almost be the same as (D). Notice that the point of the passage is to show that "evidence shows that there were women doctors and they were accepted", as stated in the right answer to question 14.
Question 18 asks us what the author thinks about this evidence. Because the whole passage hinges on the evidence, the author must at least believe that the evidence is good enough to support her claim. My answer was, "it is good enough evidence".
I also looked for a second at (B). But then saw (D). Notice that in many RC questions the smaller language usually wins in answers, unless we are given evidence in the passage to suggest otherwise. Analyze (B) and (D), and ask yourself what is the more reasonable answer to conclude from the passage.
Notice that there is a world of difference between (B) and (D). (B) tells us that the author loves the evidence, and then talks about some "crucial questions". What crucial questions? Is what you should ask yourself.
Also notice that if (B) was the right answer, it would imply that (D) is also correct. If she is optimistic, then she is more than confident about the evidence. Look for answers that don't raise any red flags when you read them. So the answers for RC tend to be passive and small, unless the author provides evidence to the contrary.
Hope that helps!