Forward prices for gold, in dollars per ounce, for the next five years are 1350, 1400, 1560, 1675, and 1756, respectively. A mine can be opened for 3 years at a cost of $2,000. Annual mining costs are a constant $500 and interest rates are 5.0%. When should the mine be opened to maximize NPV? (the answer is year 3, please show calculation