I never considered him to be a person who would (1)/ go back on his promise and (2)/ then do not even apologise. (3)/ No error (4)

Answer

3

Explanation

do (Aux. V.) will not be used because
– Each clause has to be structured in a way that is a complete sentence on its own.
Look at the structure below:
I never considered him to be a person who would go back on his promise. (Senterice I)
I never considered him to be a person who would not even apologize. (Sentence II)
Combining the two sentences
- I never considered him to be person who would go back on his promise and not even apologise. Hence, not even apologise is the right usage. Use of -
would do not even apologize is incorrect.