Given the following information, what is the total cost of unused capacity? Cost of material supplied is $$3,850$; Cost of material used is $$3,200$; Cost of material used per cake is $$3\mathrm{.}2$; Cost of material supplied per cake is $$3\mathrm{.}85.$

A$.$ $$650.$

B$.$ There is no unused capacity.

C$.$ $$3,250.$

D$.$ $$6,500.$

E$.$ $$\mathrm{.}65.$