A seller is considering the effect on firm value from transitioning a long$-$time customer from cash terms to credit terms. For years, the customer has purchased $250$ units every $60$ days. The seller believes that extending credit terms of net $60$ days will encourage the customer to increase their purchase quantity to $300$ units. Each unit sells for $$50$ and the seller incurs immediate variable costs of $$30$ per unit. The seller has an annual opportunity cost rate of $4\mathrm{.}65\%.$ Assuming that the customer just placed an order on cash terms, what is the NPV of extending credit if sales continue every $60$ days in perpetuity?

Select one:

a$.$ $$229,053$

b$.-$$$659,108$

c$.$ $$116,807$

d$.$ $$775,929$