Which of the following statement is correct? None of the other statements is correct. If the dividend yield on the S&P500 index exceeds the US risk-free interest rate, a short futures position in S&P500 index earns a positive roll return if the futures curve does not move. If the convenience yield of a consumption commodity is higher than the storage cost, the futures curve for the commodity is downward sloping. More than one of the other statements is correct. If the storage cost of a consumption asset is lower than the risk-free interest rate the futures curve for the consumption commodity is upward sloping