Why Is a Currency Put or Call Not Profitable to Exercise

Why is a currency put or call not profitable to exercise when it is "at the money"?

A) because the spot equals the price but the premium is not recovered if it is exercised resulting in a loss
B) When an option is "at the money," the Exchange will charge a higher fee.
C) When it is "at the money," the Exchange shuts down trading of the option contract.
D) The Exchange will use mark to market accounting to record a loss.