What defines a prime number?

A prime number is specifically defined as a number that has exactly two different factors: itself and one. This means that a prime number can only be divided evenly by one and by itself, and no other whole numbers. For example, the number 5 is prime because it can only be divided by 1 and 5 without leaving a remainder.

The definition excludes any number that has more than two factors, such as composite numbers, which can be divided by other numbers as well. Thus, a prime number cannot have factors such as 2, 3, or any other number apart from one and itself. This makes option C the correct choice, as it accurately conveys the core characteristic of prime numbers.