WILL GIVE A BRAINLIEST!! PLEASE HELP

Determine whether the sequence below is a geometric sequence and, if so, find a formula that describes the sequence.

3, 1, 1/3, 1/9, …

A.
a(n)=3x(1/3)n-1
B.
a(n)=1/3(3)n-1
C.
a(n)=3x(n-1)^3
D.
The sequence is not a geometric sequence.