On March $1,$ Dilbert Inc sells $2,000$ units to Tundra Inc for $$5/$unit or a total of $$10,000.$ Dilbert's cost is $$\frac{3}{?}$ unit. Terms are $\frac{2}{15},\frac{n}{45}$

On March $5,$ Tundra returns $300$ units because they are the wrong size for Tundra's customers.

On March $7,$ Tundra returns $150$ units because they are defective.

If Tundra pays on March $25,$ what amount of cash must they pay to Dilbert, assuming all applicable discounts are taken?

$7,750$

$10,000$

$9\mathrm{.}800$

$7\mathrm{.}595$