Answer:
The correct answer is rational numbers.
Explanation:
We consider that a set is closed when the two elements that are part of an operation result in an element belonging to the same group.
As for rational numbers, they are all those that can be represented as the quotient of two whole numbers or, a whole and a positive natural.
These types of numbers are considered in a set closed under addition, subtraction, and multiplication.
Given this information we can say that the correct answer is rational numbers.