The table below contains the implied volatility and option price for a series of call options of varying strike prices and varying time to expiration. The current stock price is $74.90. Suppose I want to buy the at-the-money option which is relatively cheapest. Which option should I buy? Implied Volatility December January April (T=0.17) (T=0.25) (T-0.50) 0.300 0.280 0.320 Actual option price December January April (T=0.17) (T-0.25) (T-0.50) 4.35 5.89 6.95 X 70 75 0.284 0.275 0.290 2.46 3.02 4.40 80 0.257 0.269 0.285 0.77 1.13 2.20 December, X-75 O January, X=75 January, X=70 December, X=80 O April, X=75