This is a very sloppily written question. You can already tell from the confusing spelling mistakes – "students'" is misspelled as "student's" three times in as many sentences, and this is not just an irrelevant formal glitch but makes it more difficult to understand the question (as perhaps evidenced by your reference to "Manuel's score" in a comment, which makes no sense since the question is about the scores of Manuel's students, not Manuel's score).
I cannot think of any reasonable definition of "generally higher" (much less an obvious one that could be presupposed without providing it) that would make any of the first three answers correct. You can extend your example by an arbitrary number of scores of $1$ and $4$, e.g. $(1,1,1,2,4,4,4)$ and $(1,1,1,3,3,4,4)$, and it makes no sense by any stretch of the expression "generally higher" to apply it to that case (and the expression "no discernable difference" is even worse – what would prevent a difference from being discerned?).