Question

Why is it important to record audio of silence in the area in which you are filming?

You want to make sure it is perfectly quiet before you begin filming.
It can be used to show the crew what it means for the set to be silent.
The editors can use it to cancel out excessive noise in other shots in the editing process.
All areas have unique “silence” since there is always some background noise.

Answer 1

I think the answer is D.

Answer 2

The correct option is D.
Time of complete silence is very rare, because it is impossible to achieve complete silence, some background noise usually exist. It is important to record audio of silence when filming because this will allows one to determine the level of silence that will be perfect for the recording of the film.