Show calculations please.

You are valuing a mining company, with substantial undeveloped reserves. The firm has $100$ million shares trading at $ $25$ per share, and $ $1\mathrm{.}5$ billion in debt outstanding $($market values$).$ The cost of equity for the firm is $12\%$ and the after$-$tax cost of debt is $5\%.$ If the existing reserves of the firm are expected to generate $ $350$ million in after$-$tax cash flows each year for the next $10$ years $($FCFF$)$ and we assume this the value being attached to the $$developed resources$,$ estimate the value being attached to the $$undeveloped reserves$$ by the market at existing prices $($both debt

and equity$).$ Pick the closest integer

A$.$ $ $2,209$ million

B$.$ $ $2,106$ million

C$.$ $ $1,894$ million

D$.$ $ $1,790$ million