Which of the following is the function representing the graph below?

f(x) = 4^x
f(x) = 4^(x) − 3
f(x) = 4^(x) + 3
f(x) = 4^(x + 3)

We have that

using a graph tool
see the attached figure 

 case A) f(x) = 4^x
this function is not represented in the graph

case B) f(x) = 4^(x) − 3
this function is not represented in the graph

case C) f(x) = 4^(x) + 3
this function is  represented in the graph

case D) f(x) = 4^(x + 3)
this function is not represented in the graph

the answer is
case C) f(x) = 4^(x) + 3