What type of flaw is this?

Dean: The mathematics department at our university has said that it should be given the sole responsibility for teaching the course Social Sciences.

Correct Answer choice B:

"purports to refute a view by showing that one possible reason for that view is insufficient"

Wording is a bit hard for me to understand. What type of flaw is this?

edit:

I got rid of C, D, E and chose A between A & B:

"presumes, without providing justification, that expertise in a subject does not enable one to teach that subject well"

I think the key deduction I should have made was that for A, the stimulus/argument does not talk about a subject being taught "well". So this should have clicked for me as a flaw that is out of scope.

Admin note: edited title; please use the format of "PT#.S#.Q# - [brief description of question]"

I deleted the rest of the stim because it is against our Forum Rules to post LSAT question verbatim on the Forum

https://classic.7sage.com/lsat_explanations/lsat-55-section-3-question-25/