What other answers are correct?

2 answers:

B) integer

C) Rational

The original expression simplifies to -4 which is part of the set of integers {..., -3, -2, -1, 0, 1, 2, 3, ...}

We can write -4 as a fraction of two integers -4 = -4/1, so it is also a rational number.

Because it's rational, it cannot be irrational.

The set of whole numbers is {0, 1, 2, 3, ...} which doesn't involve negative values. If you want to include negative values, then use the set of integers.