Which one of the following is given by the passage as a reason for the difficulty a lawyer would have in determining ...

I am confused with how we are able to cross out choice (D). The reason for this is because the passage clearly states "unless one is capable of concentration on a topic so intently that one loses track of one's own identity. But the instructor says that the topic of losing track of one's own identity isn't anywhere in the passage. Also, D cannot be true even if D's content was in the passage because the choice starts off with "some people who are NOT good students derive pleasure from losing track of their own identities" but you would be a good student if you derived pleasure from losing track of your identity. So this answer choice could not be true.