Let us assume that the expected return on a stock is 12% and the risk-free rate is 6%. An option on the stock can be valued by A. B. C. D. assuming that the expected growth rate for the stock price is 12% and discounting the expected payoff of the option at 6%. assuming that the expected growth rate for the stock price is 12% and discounting the expected payoff of the option at 12%. assuming that the expected growth rate for the stock price is 6% and discounting the expected payoff of the option at 6%. assuming that the expected growth rate for the stock price is 6% and discounting the expected payoff of the option at 12%.