1 is the multiplicative identity for……………..A. whole numbersB. integersC. rational numbersD. all of the above

In order to solve this problem one needs to know that multiplicative identity is an identity element (such as 1 in the group of rational numbers without 0) that in a given mathematical system leaves unchanged any element by which it is multiplied. Complete step-by-step answer: We know that whole numbers are a subset of integers which in turn are a subset of rational numbers. Also, 1 is the multiplicative identity for rational numbers because the product of 1 and any rational number is the rational number itself. Thus, 1 is the multiplicative identity for whole numbers, integers and rational numbers. Hence, the correct option is C. Note: In this problem you just need to know that rational numbers are represented in p/q form where q is not equal to zero and when it is multiplied by 1 it gives that particular rational number only. Knowing these things will solve your problem.