For the following situations, the only changes are the ones described (for example, the risk-free rate, strike price, and dividend payout do not change):

If the stock price falls while the call price rises, the call option's implied volatility must have _______. If the time to maturity for a put falls and the put price rises, the option's implied volatility must have _____.

a)decreased; increased

b) increased; decreased

c) increased; increased

d) decreased; decreased