My uncle died . . . . . . . the war. A. during B. with C. at D. for

The correct answer is A. during.

The word “during” means “at some time within the period of time that something happens.” In this case, the uncle died at some time within the period of time that the war was happening.

The word “with” means “together with.” In this case, it would not make sense to say that the uncle died together with the war.

The word “at” means “in a particular place.” In this case, it would not make sense to say that the uncle died in the war.

The word “for” means “in the course of.” In this case, it would not make sense to say that the uncle died in the course of the war.