Inventory records for Sport Company revealed the following:

Date Transaction Number of Units Unit Cost

Apr. $1$ Beginning inventory $500$ $$2\mathrm{.}40$

Apr. $20$ Purchase $4002\mathrm{.}50$

The company sold $700$ units of inventory during the month. Ending inventory assuming weighted$-$average cost would be $($round weighted$-$average unit cost to four decimals and final answer to the nearest whole dollar$)$:

A:$502$

B:$490$

C:$480$

D:$489$