Final answer:
The arbitrage opportunity is to short the spot and long the forward when the futures price is $1600. The arbitrage opportunity is to long the spot and short the forward when the futures price is $1770.
Step-by-step explanation:
To determine the arbitrage opportunity, we compare the futures price to the equilibrium price. If the futures price is lower than the equilibrium price, there is an opportunity for arbitrage. In this case, the equilibrium price is $1683.98. Case 1 is when the futures price is $1600, which is lower than the equilibrium price. Therefore, the arbitrage opportunity is to short the spot and long the forward. On the other hand, in Case 2, where the futures price is $1770, which is higher than the equilibrium price, the arbitrage opportunity is to long the spot and short the forward contract.