Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Solve the problem.
-Let $\mathrm { f } ( \mathrm { x } )$ compute the cost of a rental car after $x$ days of use at $\$ 28$ per day. What does $\mathrm { f } ^ { - 1 } ( \mathrm { x } )$ compute?

A) The number of days rented for 28 dollars
B) The cost of rental for 28 days
C) The number of days rented for $x$ dollars
D) The cost of rental for $x$ days