Let $p$ be the price of an item and $q$ be the number of items sold at that price, where $q=f(p)$. What do the following quantities mean in terms of prices and quantities sold?

1. $f(25)$ is the

A. median number of items sold if the price is no more than 25.
B. rate at which items are sold when the price is 25.
C. average price of the first 25 items sold.
D. price for which 25 items are sold
E. rate at which the price is changing when 25 items are sold.
F. number of items sold when the price is 25.
G. revenue generated by the sale of 25 items.

2. $f^{-1}(40)$ is the

A. revenue generated by the sale of 40 items.
B. price at which 40 items will be sold.
C. rate at which the price is changing when 40 items are sold.
D. average price of the first 40 items sold.
E. number of items sold when the price is 40.
F. number of the first 40 items that are returned for refund.
G. rate at which items are sold when the price is 40.