Answer:
Option: B is the correct answer.
The equation of the new function is:
B. f(x) = 2^{3x}
Explanation:
For a given function f(x) the transformed function:
g(x)=f(bx) gives a horizontal compression or stretch depending on b
if b>1 then the graph is compressed.
and if 0 < b <1 then the graph is stretched.
We are given a parent function f(x) as:

Here we have b=3
Hence, the equation of the new function will be:

Hence, the correct answer is : Option: B