Fill in the blanks with the most appropriate words.
A: What _____ you _____?
B: I'm a lecturer.
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 A is correct as the subject is singular/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 question's subject is singular and starts with what. The other blank cannot take doing as the question is a general question and do is used as an ordinary verb here.
The correct answer is A)do/do