When moving from valuing an option on a non-dividend paying stock to an option on a currency which of the following is true?

Group of answer choices

The risk-free rate is replaced by the excess of the domestic risk-free rate over the foreign risk-free rate for discounting

The risk-free rate is replaced by the excess of the domestic risk-free rate over the foreign risk-free rate when p is calculated

The risk-free rate is replaced by the excess of the domestic risk-free rate over the foreign risk-free rate in all calculations

The formula for u changes