Mashaal Masha
$$f(x)=9(4)^{x}$$

The function $f$ is defined by the given equation. If $g(x)=f(x+2)$, which of the following equations defines the function $g$?
Difficulty: Hard
A: 

$g(x)=18(4)^{x}$

B: 

$g(x)=144(4)^{x}$

C: 

$g(x)=18(8)^{x}$

D: 

$g(x)=81(16)^{x}$