That which cannot be avoided:

Inevitable
Irreparable
Incomparable
Indisputable

The correct answer is A. Inevitable.

Inevitable means certain to happen; unavoidable.

Irreparable means not able to be repaired or made good.

Incomparable means so good that no other thing is as good.

Indisputable means not able to be doubted or questioned.

Of the above, only inevitable means certain to happen and cannot be avoided.