He had to try to make the call in the middle of the night, it was hard to communicate using only a what?
Options:
- communicating
- response
- yelling
- hanging up
- whisper Let's think step by step:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
It is difficult to communicate through a whisper. Whisper means to speak softly. So, the answer is whisper.