Answer:
Option C.) Geometric, common ratio = 3
Step-by-step explanation:
we know that
In a Geometric Sequence each term is found by multiplying the previous term by a constant
The constant is called the common ratio
In this problem we have
For x=1, f(1)=3
For x=2, f(2)=9
For x=3, f(3)=27
For x=4, f(4)=81
so
f(2)/f(1)=9/3=3 -----> f(2)=3*f(1)
f(3)/f(2)=27/9=3 -----> f(3)=3*f(2)
f(4)/f(3)=81/27=3 -----> f(4)=3*f(3)
f(n+1)/f(n)=3 -----> f(n+1)=3*f(n)
therefore
This is a Geometric sequence and the common ratio is equal to 3