Here's the question you clicked on:
buthead
How many four-letter arrangements are possible from the four-letters given below? MNOR A. 24 B. 8 C. 32 D. 4
I think it's A, however, you'll want someone to confirm that for you. This is because it would be 4!, therefore 4 x 3 x 2 x 1, which is 24, and since there are no repeated letters, nothing needs to be divided.
Yup, @brinazarski is correct. It's 4!, no repeated letters and any permutation is valid.
Thanks for the medal guys :)