Which of the following sets includes non-negative integers only?

The correct answer is the set of whole numbers, which includes all non-negative integers. Whole numbers start from zero and include all positive integers (1, 2, 3, ...) without including any negative numbers. This makes them a perfect fit for the definition of non-negative integers, which are typically defined as zero and all positive integers.

In contrast, the restrictions of natural numbers generally refer to positive integers beginning from 1, which means they do not include zero. Negative integers consist only of numbers less than zero, which are not non-negative. Rational numbers, while encompassing all whole numbers, also include negative numbers and fractions, thereby failing to exclusively represent non-negative integers. Thus, the set of whole numbers is the only option that is entirely composed of non-negative integers.