A bookstore has an annual demand for $104,000$ copies of a best$-$selling book. It costs $$0\mathrm{.}90$ to store one copy for one year, and it costs $$80$ to place an order. Find the optimum number of copies per order.

A$)4416$ copies

B$)3870$ copies

C$)4300$ copies

D$)4532$ copies