Sentences are given with blanks to be filled in with an appropriate word(s). Four alternatives are suggested for each question. Choose the correct alternative out of the four.
It was very kind of you to do the washing-up, but you__it.

Options

A. didn't have to do
B. hadn't to do
C. mightn't have done
D. mustn't have done

Answer

D

Explanation

Here, mustn.t have done is the right usage.