Ans: C
There are three methods transforming one graph to the other. The first method is translating the left graph to the right $4$ units. Then the two functions will be $y=f(x)$ and $y=f(x-4)$. However, there is no such option.
There are three methods transforming one graph to the other. The first method is translating the left graph to the right $4$ units. Then the two functions will be $y=f(x)$ and $y=f(x-4)$. However, there is no such option.
The second method is translating the right graph to the left $4$ units. Then the two functions will be $y=f(x)$ and $y=f(x+4)$. However, there is no such option.
The last method is reflecting one graph about $y$-axis to the other. Then the two functions will be $y=f(x)$ and $y=f(-x)$.