Best Online CAT Coaching

Option A - The author never mentions at any point in the passage that the brains of men and women are alike. She says not all boys can do Science, and not all girls cannot do Science. This means that brains are neither alike nor different on the basis of gender. Hence, option A can be eliminated.
Option C - While the author stresses the importance of not stereotyping someone based on gender, the author does not mention anything about society having to break away from attempts at gender stereotypes explicitly. Hence, option C can be eliminated.
Option D - This is the specific point of conclusion that the author is trying to arrive at. It can clearly be seen from the statement, "Her conclusive findings establish that no brain differences can be found that are solely gender related." This is more focussed than option B. Hence, option B can be eliminated. Option D is the right answer.