Some teachers claim that students would not learn curricular content

Premise : Students with intense interest in the material would learn it without the incentive of grade, while the behavior of students lacking all interests in the material is unaffected by incentive of grade.

Conclusion : The incentive of grades, therefore, serves no essential academic purpose.

Ques : The reasoning in the argument is flawed because the argument

Pre-thinking : On relating the Premise to the Conclusion, we can see that the Premise only talks about students with extremes, one type of students with intense interest and other type with no interest at all. Ane conclusion is done for a general academic purpose.
Now, lets ask ourselves
- are there are only these two types of students exist?
- has the argement mentioned that there is no other type of students?
- If the ans to above these ques is "No", then how can the author make a general conclusion about the acedemic purpose ?
And, this is the gap or flaw in the statement.

Lets analyse the answer choices now :
(A) take for granted that the only purpose of school is to convey a fixed body of information to students - Incorrect, the author does not make any assumption about the purpose of school.

(B) takes for granted that students who are indifferent to the grades they receive are genuinely interested in the curricular material - Incorrect, the author did not takes into account but states that students who are intensely interested in curricular would learn the curricular irrespective of the incentives of grades.

(C) fails to consider that the incentive of grades may serve some useful nonacademic purpose - Incorrect, this may or may not be true but is not related to the conclusion at all.

(D) ignore the possibility that students who lack interest in the curricular material would be quite interested in it if allowed to choose their own curricular material - Incorrect, the conclusion is not related to opting of the curricular material by the students but to learn the curricular.

(E) fails to consider that some students may be neither fascinated by nor completely indifferent to the subject being taught - Correct, the author does fail to address that there could be some students who do not have extreme liking or disliking of the curricular and their reaction to learn as an incentives of grade.