Please help I've posted this question 3 times and every time it has been wrong!

The common shares of Twitter, Incorporated (TWTR) recently traded on the NYSE for $81 per share. You have employee stock options to purchase 1,000 TWTR shares for $86 per share. The options expire in three years. Assume that the annualized volatility of TWTR stock is 71 percent and that the interest rate is 3.3 percent. (Assume the options are European options that may only be exercised at the maturity date.) a. Is this option a call or a put? Call Put b. Using an option pricing calculator such as the one at erieri.com/blackscholes, estimate the value of your TWTR options. Note: Round your intermediate calculations to 2 decimal places and final answer to nearest whole dollar. c. What is the estimated value of the options if their maturity is six months instead of three years? Note: Round your intermediate calculations to 2 decimal places and final answer to nearest whole dollar. d. What is the estimated value of the options if their maturity is three years, but TWTR's volatility is 46 percent? Note: Round your intermediate calculations to 2 decimal places and final answer to nearest whole dollar