The implied volatilities for strike prices of 1.1 and 1.2 when the time to maturity is 3 months are 20% and 22%. The implied volatilities for strike prices of 1.1 and 1.2 when the time to maturity is 9 months are 17% and 20.2%. What is the implied volatility for the strike prices of 1.1 for a time to maturity of 6 months?

Select one: a. 20.10% b. 8.50% c. 21.10% d. 19.40% e. 18.50%