Option A is the right answer.
A coherent paragraph should have a sound opening statement and supporting arguments to follow it. This question asks us to form a coherent paragraph, and choose the sentence that doesn’t fit in (the odd one out).
In the given order of sentences, Option D, C, B, E form a coherent paragraph which argues against rumination.
Here, rumination(n): thinking carefully about something for a long period
Option A argues for self-examination and rumination as quoted by Socrates. Therefore, Option A is the odd one out.