Find the Number of Distinguishable Permutations of the Group of Letters

Multiple Choice

Find the number of distinguishable permutations of the group of letters.
$$\mathrm { G } , \mathrm { A } , \mathrm { U } , \mathrm { S } , \mathrm { S }$$

A)
60

B)
120

C)
30

D)
5

E)
15