01. WHOLE NUMBERS
Explanation:
1
Solution:
A multiplicative identity is a number which when multiplied with any number, the number is unchanged.
For example: 1 × 7 = 7, 1 × 9 = 9, 1 × 100 = 100 etc.
Thus, 1 is multiplicative identity in the set of whole numbers is 1.
Hence, the correct option is (c).