What is the cash$-$flow cost of hedging translation exposure with a currency option?$$

Question $8$ options:

The interest rate differential between the foreign subsidiary and the parent's currencies.$$

The unknown$($at times of hedging$)$ speculative gain$/$loss resulting from exercising the option $+$ option premium$$

The unknown $($at times of hedging$)$ percentage of the actual foreign currency depreciation$/$appreciation$.$

The option premium on the currency in which the exposure is measured