What defines a whole number in mathematics?

A whole number in mathematics is defined as a number that is non-negative and does not contain any fractional or decimal parts. This set of numbers includes zero and all positive integers (1, 2, 3, etc.). Thus, when considering the definition of whole numbers, option C is the most accurate because it explicitly states that whole numbers include zero and all positive numbers.

The property of including zero is crucial because it differentiates whole numbers from just positive integers, which only encompass numbers greater than zero. Understanding this helps to clarify the concept of whole numbers as a foundational element in mathematics, distinct from other sets of numbers like negative integers or fractions.