Foxy Socks offers the following options: each pair of socks costs $21/pair, but if you buy 7 or more, they are $17/pair.

A. Each pair of socks, costs $21/pair.
B. If you buy 7 or more, they are $17/pair. Consider the person with a demand for socks: P = 56 - 7 Q. Based on a willingness to pay analysis, the better option is __ ____. This option provides __ ____ dollars in additional surplus.