The expression $"\frac{3}{10},$ net ${45}^{?}$ means that the customers receive a $3\%$ discount if they pay within $10$ days; otherwise, they must pay in full within $45$ days.

What would the seller's cost of capital have to be in order for the discount to be cost justified?

$30\mathrm{.}2857\%$

$34\mathrm{.}2857\%$

$35\mathrm{.}2857\%$

$31\mathrm{.}2857\%$