【正确答案】 B

【答案解析】Rhetorical construction; Verb form; Diction
Conditional constructions require specific verb tenses. For a present condition, like this debate between academicians, the subordinate clause introduced by //'uses the present indicative, and the main clause uses the future tense: y will happen (main clause) only if happens (subordinate clause). Logically, the course is to be both separate and required, so the two adjectives should equally modify the noun and thus be separated by a comma: separate, required course.
A The verb tense in the if clause is incorrect. The adverb separately should be the adjective separate.
B Correct. This sentence has the correct verb tense, and the two adjectives equally modify the noun.
C The placement of only distorts the meaning; it should precede if. A course required separately is unclear.
D The verb tense in the if clause is incorrect. The placement of only distorts the meaning.
E The verb tense in the if clause is incorrect. The placement of only distorts the meaning. The adjective separate should be used instead of the adverb separately and should precede the noun.
The correct answer is B.