The correct answer is D.

Since the manager is receiving a foreign currency payment (€500,000), the risk is that the euro will depreciate against the domestic currency before the payment is received. An option contract (specifically, a put option on the euro) is appropriate here because:

• It limits the downside risk: The manager can lock in a minimum exchange rate by exercising the put option if the euro weakens.
• It preserves the upside potential: If the euro appreciates against the domestic currency, the manager can let the option expire worthless and convert the euros at the more favorable spot rate.

Choice A is incorrect. Forward contracts do not allow flexibility in exercising the contract — they are obligations that must be fulfilled.

Choice B is incorrect. While an option provides a guaranteed minimum exchange rate (the strike), it does not guarantee the actual exchange rate used. Moreover, the manager would need to buy a put option on the euro (right to sell euros), not an option that locks in a guaranteed rate.

Choice C is incorrect. Although forwards generally have no upfront premium cost (beyond potential margin/collateral requirements), the decision between a forward and an option should be based on the risk profile and the desire to retain upside potential, not just on upfront costs. Additionally, this choice ignores the asymmetric risk protection that an option provides.

Choice D is correct because it best captures the key advantage of using an option: asymmetric payoff — protection against adverse movements while retaining the benefit of favorable movements.