The multiplicative identity of integers is:

The multiplicative identity of integers is:

• A. 0
• B. -1
• C. 2
• D. 1

Answer: (D)

For multiplication, the identity element is the number that leaves every integer unchanged when you multiply by it. In the integers, that number is 1, because any integer a satisfies a × 1 = a. The other options don’t work as identities: multiplying by 0 gives 0, not a; multiplying by -1 flips the sign, giving -a; multiplying by 2 doubles the value, giving 2a. Only 1 leaves every integer unchanged, so it is the multiplicative identity (and is unique).

For multiplication, the identity element is the number that leaves every integer unchanged when you multiply by it. In the integers, that number is 1, because any integer a satisfies a × 1 = a.

The other options don’t work as identities: multiplying by 0 gives 0, not a; multiplying by -1 flips the sign, giving -a; multiplying by 2 doubles the value, giving 2a. Only 1 leaves every integer unchanged, so it is the multiplicative identity (and is unique).