Which of the following would represent the most appropriate definition for implied volatility? (a) It is the volatility of the underlying asset's returns implied from the price of a traded option and an option pricing model (b) It is the volatility of the underlying asset's returns implied from a statistical model such as GARCH (c) It is the volatility of an option price implied from a statistical model such as GARCH (d) It is the volatility of an option price implied from the underlying asset volatility