I'll be home . . . . . . . . 6 o'clock.

A. in

B. since

C. on

D. by

Answer: Option D

Solution(By Examveda Team)

As a preposition of time, 'by' means before a specific time. 'By' shows a time limit for something to happen. An event must happen before a specific time is reached. For example - Please send me the report by Tuesday.