-81, 108, -144, 192, ...
which formula can be used to describe the sequence?
A. f(x)= -81 (4/3)^x-1
B. f(x)= -81 (-3/4)^x-1
C. f(x)= -81 (-4/3)^x-1
D. f(x)= -81 (3/4)^x-1