Topic: Subject Verb Agreement,

Best Answer Explained in Below-:

The sentence "They as well as he ----- incorrect." involves a grammatical structure known as a compound subject. When using "as well as," the verb agrees with the main subject of the sentence rather than the additional part introduced by "as well as."

In this case, the main subject of the sentence is "They," which is plural. Therefore, the verb must also be in a plural form to maintain subject-verb agreement. Looking at the options:

- A) "is" is singular and does not match the plural subject.
- B) "are" is plural and correctly agrees with "They."
- C) "will" can indicate future tense but does not match in form.
- D) "was" is past tense and also singular, failing to agree with "They."

Thus, the only option that correctly maintains the grammatical structure and agrees with the plural subject "They" is option B: "are." The completed sentence reads: "They as well as he are incorrect," correctly reflecting that the group "They" is being referred to in the present tense, making it the appropriate choice.