Answer-Which of the following is the theme of the passage?

In the passage the author mainly talks about PSW and how its symptoms match with depression. So a is correct. He argues however, that since PSW and depression share common symptoms so it can be a new variant of depression. But the author argues it to prove the researchs claim. So b and c are wrong. Importance of grounding has been introduced to give a base to the readers that what the passage is about. So d Is wrong. E is wrong because the passage doesnt talk about any complexities in segregating the natural kinds.