Select the most appropriate option to fill in the blank.

______ you don’t want to sleep, then leave this room.

If

The most appropriate option to fill in the blank is if.

The word if is used to introduce a condition or possibility. In this case, the sentence is saying that if you don't want to sleep, then leave this room. This means that you are allowed to leave the room if you do not want to sleep.

The other options are not correct.

• As means because or since. It cannot be used in this sentence because it does not introduce a condition or possibility.
• So means therefore or consequently. It cannot be used in this sentence because it does not introduce a condition or possibility.
• Whether means if or whether or not. It can be used in this sentence, but it would mean that you are asking if you can leave the room if you do not want to sleep.