Topic: Subject Verb Agreement,

Best Answer Explained in Below-:

The sentence "They as well as he ----—- incorrect." includes a compound subject that requires careful consideration for verb agreement. In English grammar, when using phrases like "as well as," the verb typically agrees with the subject that is closest to it, which in this case is "they."

The subject "they" is plural, while "he" is singular. However, the phrase "as well as" indicates that "they" is the primary subject despite the presence of "he." Thus, the verb must reflect this plurality.

Looking at the options:

A) "is" - This is singular and does not agree with "they."
B) "are" - This is the correct plural form that agrees with "they."
C) "will" - This is future tense and does not fit within the context.
D) "was" - This is past tense and singular, which does not match the plural subject.

Therefore, the correct answer is B) "are," making the complete sentence "They as well as he are incorrect," correctly indicating that the plural subject requires a plural verb.