If a commodity has a spot price of $5 and a one year futures price of $7 with a 10% interest rate and $0.50 storage cost you would do the following:

a) Sell spot and buy forward and earn $0.50

b) Buy spot and sell forward and earn $1

c) Buy spot and sell forward and earn $0.50

d) Sell forward and buy spot and earn $1.50

e) Nothing as there are no arbitrage opportunities

Please show your work and explanation/reasoning.