The person in the stimulus DOES break a promise ... he doesn't lie to the teacher when he promised to. So the teacher wants him to prioritize his lies. Choice D is clearly it.
No one has done anything in the stimulus in terms of promise breaking or not breaking. You are going far beyond the realm of the question.
Incorrect. This whole passage IS ABOUT PROMISE BREAKING. Let's do this piece by piece.
The teacher says you shouldn't break promises, right? Yes. But she then somewhat undermines herself when even though you promised that girl you would lie to me, but we have an implicit promise to tell the truth, therefore you should tell the truth.
So, the guy has made two contradictory promises:
Implicit: To always tell the truth
Explicit: To lie to the teacher.
Teacher says he should should implicit over the explicit. Therefore, yes, some implicit promises are worse to break than some explicit.
I know it may not be so comforting, but I am 100% sure that this one is D and am surprised by how long this has carried on.