ABC company is attempting to minimize total inventory cost. The cost of each unit is $$2\mathrm{.}25.$ The cost of capital is $15\%$ and the physical cost of maintaining this inventory is currently running at $7\%.$ The purchasing officer can place an order in $25$ minutes with materials and overhead cost of $$7\mathrm{.}50$ per order. The purchase officer is currently paid $$18\mathrm{.}00$ per hour. Records show, average weekly sales to be $12,000$ units. How many units should ABC order?

A$.6250$ units

B$.6050$ units

C$.6350$ units

D$.6150$ units