Solve for the Weighted Average Cost of Capital $13.00 \% \quad K _ { l } =$

Solve for the weighted average cost of capital: $13.00 \% \quad K _ { l } =$ cost of equity capital for a leveraged firm
$5 / 7 \lambda =$ debt-to-total-market-value ratio
$8.0 \% \quad i =$ before-tax borrowing cost
$40.0 \% \quad \tau =$ marginal corporate income tax rate

A) 8.67%
B) 8.00%
C) 7.60%
D) 7.33%
E) 7.14%