What is the answer to this question?

Answer:
B
Step-by-step explanation:
The graphs of the function and of its inverse function are always symmetrical about the line y = x.
The diagram shows the graph of the function f(x) (blue line).
The line with the equation y = x is the I quadrant bisector, so symmetrical graph to the grph of f(x) is red graph - graph of the function g(x).
Hence, correct option is B.