Suppose the current value of a popular stock index is 648.50 and the dividend yield on the index is 2.6%. Also, the yield curve is flat at a continuously compounded rate of 6.0%. a. If you estimate the volatility factor for the index to be 16%, use the Black-Scholes model to calculate the value of an index call option with an exercise price of 665 and an expiration date in exactly three months. You may use Appendix D to answer the question. Do not round intermediate calculations, Round your answer to the nearest cent. $ b. If the actual market price of this option is $16.90, calculate the implied volatility coefficient. Do not round intermediate calculations. Round your answer to two decimal places. %