In our discussion on Hospital expenses I emphasized thinking of both rate

and volume for any specific type of expense. Which of the following are

examples of this concept?

For administrative salary cost, volume is the number of administrators and rate

is the total salary expense

For nursing salary cost, volume is how many patients a nurse can take and rate

is the average hourly rate paid to those nurses

For surgical hip implant cost, volume is the number of cases done at the

Hospital and rate is how much each implant costs.

Both a and c

Both $b$ and $c$

Both a and $b$