8. How does the price of a put option respond to the following changes, other things equal? (a) Stock price increases. (b) Exercise price is increased. (c) Risk-free rate increases. (d) Expiration date of the option is extended. (e) Volatility of the stock price falls. (f) Time passes. 9. Which one of the following is true? (a) Call premium is increasing in the expected return on the underlying asset. (b) Call premium is decreasing in the expected return on the underlying asset. (c) The expected return on the underlying asset is irrelevant. (d) Options (a), (b), and (c) are all incorrect