Which graph shows a function whose inverse is also a function?

On a coordinate plane, two curved graphs are shown. f (x) sharply increases from (negative 0.5, negative 5) to (0, negative 2) and then sharply changes directions and curves down to (0.5, 4.5). The curve then sharply changes direction and goes up through (1, 0). The inverse of f (x) curves slightly up from (negative 5, negative 1) to (negative 2, 0). The curve then sharply changes directions and go to the left toward (negative 3.5, 1). The curve then changes directions and goes through (0, 1) and gradually increases.

On a coordinate plane, 2 parabolas are shown. f (x) opens down and goes through (negative 1, negative 5), has a vertex at (0, 1), and goes through (1, negative 5). The inverse of f (x) opens to the left and goes through (negative 5, 1), has a vertex at (1, 0), and goes through (negative 5, negative 1).

On a coordinate plane, 2 lines are shown. f (x) has a positive slope and goes through (negative 4, negative 3), (0, negative 1), and (2, 0). The inverse of f (x) has a positive slope and goes through (negative 2, negative 2), (negative 1, 0), and (0, 2).

On a coordinate plane, 2 v-shaped graphs are shown. f (x) opens up and goes through (negative 1, 5), has a vertex at (1, 1), and goes through (3, 5). The inverse of f (x) opens right and goes through (5, 3), has a vertex at (1, 1), and goes through (3, 0).