Assume the total market value of General Motors $($GM$)$ is $$10$ billion. GM has a market value of $$4$ billion of equity and a face value of $$12$ billion of debt. What are the weights in equity and debt that are used for calculating the WACC?

Group of answer choices

$0\mathrm{.}30,0\mathrm{.}70$

$0\mathrm{.}60,0\mathrm{.}40$

$0\mathrm{.}40,0\mathrm{.}60$

cannot be determined