How can$$ exchange$-$rate risk be hedged using$$ forward, futures, and options$$ contracts?

A$.$

Firms can buy forward contracts to hedge against a fall in the exchange rate.

B$.$

Firms can buy a call option to hedge against a fall in the exchange rate.

C$.$

Firms can buy a put option to hedge against a fall in the exchange rate.

D$.$

All of the above.