Beranek Corp has $$560,000$ of assets $($which equal total invested capital$),$ and it uses no debt$$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$.$ $$112,000$

b$.$ $$224,000$

c$.$ $$784,000$

d$.$ $$400,000$

e$.$ $$336,000$