I . . . . . . . . certainly do it.

A. will

B. is

C. shall

D. none of these

Answer: Option C

Solution(By Examveda Team)

use 'will' for affirmative and negative sentences about the future. Use 'will' for requests too. If you want to make an offer or suggestion with I/we, use 'shall' in the question form. For very formal statements, especially to describe obligations, use 'shall'.