Find a Formula for the Inverse of the Function Described $$C ( x ) = \frac { 200 + 6 x } { x }$$

Find a formula for the inverse of the function described below.
-An organization determines that the cost per person of chartering a bus is given by the formula $$C ( x ) = \frac { 200 + 6 x } { x }$$ where x is the number of people in the group and C(x) is in dollars.

A) $C ^ { - 1 } ( x ) = \frac { 200 + x } { 6 }$

B) $C ^ { - 1 } ( x ) = \frac { 6 } { x - 200 }$

C) $C ^ { - 1 } ( x ) = \frac { 200 } { x + 6 }$

D) $C ^ { - 1 } ( x ) = \frac { 200 } { x - 6 }$