2. (a) The spot price of copper is $3.61 per pound. The six-month forward price of copper is $3.72 per pound. The storage costs of copper (as a proportion of the spot price) are 4 % per annum with continuous compounding. The six-month risk-free interest rate is 8 % per annum with continuous compounding. Calculate the convenience yield. (b) Explain why the convenience yield is inversely related to the level of inventories.