Which of the following correctly defines an integer?

An integer is defined as a whole number that can be positive, negative, or zero, but does not have any fractional or decimal part. This characteristic distinguishes integers from other number types, such as rational numbers, which can include fractions or decimals. The choice stating that an integer is a number with no fractional or decimal part accurately captures this essential feature of integers.

In contrast, options that mention decimal parts or measurements do not apply to integers, as integers are specifically those whole numbers without any components that would suggest fractions or decimals. Similarly, the choice that refers to a variable representation of a number does not address the definition of integers, as it pertains more to the concepts of algebraic variables rather than the properties of integer values themselves.