Problem 8. (each part is 5 points) Assume the Black-Scholes model. The digital call option pays nothing if the underlying asset finishes below the strike price or pays $1 if the underlying asset finishes above the strike price. The digital put option pays nothing if the underlying asset finishes above the strike price or pays $1 if the underlying asset finishes below the strike price. (a) State the put-call parity relationship for the digital call and digital put options on the same underlying and with the same maturity. (b) Assuming r=q=0, what are the values of these options as the volatility approaches zero? What are the values when the volatility approaches infinity