How Many Ways Can a Potential 4-Letter Word,whether or Not

Multiple Choice

How many ways can a potential 4-letter word,whether or not it has a meaning,be created out of 10 available different letters?

A) 4 * 3 * 2 * 1
B) 10 * 9 * 8 * 7/(4 * 3 * 2)
C) 10 * 9 * 8 * 7 * 6 * 5/(4 * 3 * 2)
D) 10 * 9 * 8 * 7