Directions: Find out which part of the given sentence has an error of grammar usage. If the sentence has no error, mark your answer as (D).

The leader, together (A)/ with his supporters and wife, are going (B)/ to file the nomination papers. (C)/ No error (D).

This is the correct option as this part of the sentence has the error. The sentence has subject-verb disagreement between the singular subject (leader) and plural verb (are going). The accompanying phrase only provides extra information and does not alter in any way the grammatical relationship between the subject and the verb.