A potential investor is willing to provide $$500,000$ in first$-$round financing with the expectation of a $50\%$ annual compound rate of return over the next five years. Founders currently hold $1,000,000$ million shares of stock. The venture is expected to produce $$500,000$ in net income in year $5.$ A similar firm with annual net income of $$1,000,000$ sold shares to the public for $$10,000,000.$ What is the post$-$money valuation?

a$.$ $$499,954$

b$.$ $$408,377$

c$.$ $$658,436$

d$.$ $$249,977$

Please provide me with the equation for the BA$2$ Plus calculator method.