This is correct. Professor Sedley insists that the reasoning used by Professor Beckstein would, if it were consistent, also lead to French and Spanish being disqualified as languages that fulfill the foreign language requirement — a conclusion that Sedley says is ridiculous.

Professor Sedley never claims that Professor Beckstein's conclusion that American Sign Language should not fulfill the foreign language requirement somehow contradicts the evidence Beckstein provides. Sedley actually doesn't directly mention the specifics of either Beckstein's evidence or his conclusion about American Sign Language. Instead, Sedley focuses entirely on applying the pattern of Beckstein's reasoning to the analogous case of French and Spanish.

Professor Sedley never mentions Professor Beckstein’s authority or qualifications to discuss this topic. He just criticizes the logic of Beckstein’s argument.

For this answer choice to be correct, Professor Sedley would somehow have to reinterpret the fact that American Sign Language is spoken by many North Americans. He doesn't do that. His argument doesn't directly mention American Sign Language — it relies on an analogy to a different set of languages.

Professor Sedley never says whether he agrees with Beckstein’s conclusion or not. He actually doesn't mention the conclusion itself. His point is to criticize the logic leading up to the conclusion, and say that the reason Professor Beckstein provides — that American Sign Language is the native language of many North Americans — isn't good enough to justify his conclusion that American Sign Language shouldn't count for the foreign language requirement.