Question

What's that noise?
What.....

A) is happening
B) happened
C) had happened
D) has happened

Answer 1

The sentence after filling up the blank – What is happening? It indicates the present continuous tense.

It would be the perfect answer according to the first sentence. Hence the correct answer is A.

The sentence can also written as - What has happened? Therefore option D can also be applicable.

Here the present perfect tense is used which indicates the past event having the present consequences.

Answer 2

What is that noise?

What is happening ??

The correct answer is happening .

This is because the noise is being heard currently and is a continuity of the process hence the use of present continuous tense to show that the event is going on the time if the speech