Answer:
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n! is called the factorial of n and shown as the product of the integers from 1 to n:
- n! = n * (n - 1) * (n - 2) *...* 3 * 2 * 1
The given expression can be evaluated as:
- 20! / [ 17! (3 - 1)!] =
- 20*19*18 * 17! / (17!2!) =
- 20*19*18/2 =
- 3420
Hence the correct choice is c.
