Fill in the blank in the following sentence with the most appropriate…

The correct answer is Option (3) → unless

Complete sentence: Rajesh has a weird habit of not leaving the stage unless he gets a standing ovation. Rajesh does not leave the stage if he does not get a standing ovation, so "unless" joins the two parts.

Option	Meaning and use	Example
(1) because	Because gives a reason. It would say that he does not leave the stage because he gets an ovation, which is not the sense.	She stayed at home because she was ill.
(2) as	while or since (because). Neither gives the condition needed here.	He smiled as he walked in.
(3) unless (answer)	Unless means "if not" or "except if". It joins a condition to a main clause. It usually follows a negative idea: "not ... unless ..." means the action happens only when the condition is met. Deciding clue: the negative "not leaving", which needs an "if not" condition.	I will not go unless you come with me.
(4) therefore	Therefore is an adverb that shows a result. It cannot join the two clauses, and a result makes no sense here.	It rained all day; therefore, we stayed in.