Fill in the blanks with the most suitable word from the options given…

The correct answer is Option (3) → because

Complete sentence: The desire for revenge is very dangerous because it does not diminish with time. The desire for revenge is dangerous, and the reason is that it does not diminish with time, so "because" joins the two.

Option	Meaning and use	Example
(1) whereas	contrast between two facts. The second clause explains the first, it does not contrast with it.	Riya likes tea, whereas her sister prefers coffee.
(2) while	time (during) or contrast. Neither fits a clause that gives a reason.	She listened to music while she worked.
(3) because (answer)	Because introduces the reason for what is said in the main clause.	We stayed indoors because it was very hot.
(4) so	So introduces a result. "Dangerous, so it does not diminish" turns the reason into a result, which reverses the logic.	It was raining, so we stayed indoors.