An investor is analysing the costs of two-year, European options for metal and zinc at a particular strike price. For each ton of metal, the two-year forward price is 1400, a call option costs 700, and a put option costs 550. For each ton of zinc, the two-year forward price is 1600 and a put option costs 550. The annual effective risk-free interest rate is 6%. Calculate the cost of a call option per ton of zinc