Suppose that there are no storage costs for crude oil, and the interest rate for borrowing or lending is always $4\%$ per annum. How could you make money if the June and December futures contracts for a particular year trade at $$50$ and $$51,$ respectively? Assume that the interest rate is discretely compounded and there is no daily settlements.

$1.$ There is no arbitrage opportunity.

$2.$ Borrow funds at a risk$-$free interest rate & go long on June futures & go short on December futures

$3.$ Borrow funds at a risk$-$free interest rate & go short on June futures & go long on December futures

$4.$ Invest funds at a risk$-$free interest rate & go short on June futures & go long on December futures

$5.$ Invest funds at a risk$-$free interest rate & go long on June futures & go short on December futures