Which statement defines an integer?

An integer is defined as a whole number that can be positive, negative, or zero. This definition encompasses the entire set of integers, which includes numbers like -3, 0, and 5, among others. Integers do not include fractions or decimal numbers, and they are not limited to only positive values. This is why the option that states a whole number that can be positive, negative, or zero is the correct and comprehensive definition of an integer. Other statements do not fully capture the set of integers and either limit their scope to positives or exclude essential characteristics like including zero.