Step 1 :The question is asking for the factorial of the result of the expression \((21-13)\). The factorial of a number is the product of all positive integers less than or equal to that number.
Step 2 :First, we need to calculate the result of the expression \((21-13)\).
Step 3 :Then, we will calculate the factorial of the result.
Step 4 :The factorial of a number is always an integer, so we can already eliminate option B.
Step 5 :Let's calculate this: the result of the expression \((21-13)\) is 8.
Step 6 :The factorial of 8 is 40320.
Step 7 :Final Answer: The value is an integer. \((21-13) ! = \boxed{40320}\)