Fill in the blank with the most appropriate word.
My classmates __________ on a picnic every month.
A verb is used to express an occurrence, action, or state. It is the grammatical centre of the predicate in a sentence.
An auxiliary verb is a verb which gives is used in the formation of tenses, moods, tones, etc.
Option D is correct as the subject is plural and the present simple tense is used for a present state, habits,routines, jobs, hobbies or expressing possession, generalizations, scientific statements.
The other options are wrong as the subject is not singular and the past simple tense is used for an action or a series of actions in the past.
The correct answer is D)go