Which of the following sets does the number 3 belong to?

The number 3 belongs to several sets of numbers, making the identification of its categorization important. As a whole number, it is part of the set of whole numbers, which consists of all non-negative integers (0, 1, 2, 3, ...). Additionally, 3 is classified as an integer because integers include all whole numbers and their negative counterparts. Additionally, since rational numbers are defined as any number that can be expressed as a fraction of two integers (where the denominator is not zero), and since 3 can be represented as 3/1, it fits within the set of rational numbers as well.

Thus, the correct answer encompasses the broadest range of sets that include 3: whole numbers, integers, and rational numbers. This makes it the most accurate representation of where the number 3 belongs.