When a function's inverse is found, it is found by switching the x and y terms and then solving for the new y. You could actually graph an inverse then by switching the x and y coordinates in the points that are on the function. Functions and their inverses will ALWAYS be symmetrical about the line y = x, so the one that you're after is the first choice of the 3 at the bottom. The red line and the blue line reflect through the y = x line.