X and Y are two American call options on the same stock with the same strike price. X has six month to expiration, while Y has three month to expiration. Which of the following must be true?
a. X is less expensive than Y.
b. X is more expensive than Y.
c. X is more actively traded than Y.
d. X is less actively traded than Y.
e. If the stock price increases, X will decrease in value and Y will increase in value.