Select the most appropriate option to substitute the bracketed segment in the given sentence. If no substitution is required, select No improvement.
I will not go to the party (lest you will) promise to accompany me

Options

A. A. No improvement
B. B. if you will
C. C. lest you should
D. D. unless you

Answer

D

Explanation

It is a conditional sentence which has two conditions and starts with a negative sense(will not). Unless. is a negative conditional conjunction which is generally used to describe two conditions(negative sense) together like unless you work hard, you cannot( negative sense) achieve success. Hence, unless is the most appropriate answer.