Beranek Corp has $$660,000$ of assets $($which equal total invested capital$),$ and it uses no debt$-$it is financed only with common equity. The new CFO wants to employ enough debt to raise the total debt to total capital ratio to $40\%,$ using the proceeds from borrowing to buy back common stock at its book value. How much must the firm borrow to achieve the target debt ratio?

a$.$ $$471,429$

b$.$ $$264,000$

c$.$ $$132,000$

d$.$ $$396,000$

e$.$ $$924,000$