When the phrase 'it is time/it is high time' is used then is V2 used. So, 'he starts earning his living' is the correct usage option (3).
English Grammar CTET MCQ - Verbs and Proverbs
Directions (Q.No. 57) Select the correct verb form to fill in the -blank space.
DIRECTIONS (Q.Nos.40 to 41) Choose the correct form of verb to complete the sentences.
DIRECTIONS (Q.Nos.40 to 41) Choose the correct form of verb to complete the sentences.

