Given:
The objective is to choose the correct set of numbers that is closed under subtraction.
Step-by-step explanation:
Set of closed numbers
A set of closed numbers means if an operation between any two elements present in a set produces the third element of the same set if called the set of closed numbers.
The whole numbers and natural numbers are closed only under addition and multiplication.
But subtraction of any two rational numbers will always give another rational number.
Thus, rational numbers are closed under subtraction.