how many integers are their own multiplicative inverses?

Question

a. 0
b. 1
c. 2
d. 3

is it 2 or 3? because it could be 1, -1, and 0

Answer 1

2, not 3

0 is not its own inverse. 0*0 ≠ 1
In fact, 0 has no inverse -- there is no number n such that 0*n = 1

Answer 2

The answer would be 2.
When we think of integers, there are positive and negative integers. (Positive being 1 or greater and negative being -1 or less). However, 0 is a neutral number, not positive nor negative so 0 will be excluded.