Given the following costs and activities for Falcon Company's electrical costs, use the high-low method to compute Falcon's variable electrical costs per machine hour Costs Machine Hours April $3,600 15,000 May 3.000 11,000 June 4.200 21,000 Oa. $0.71 per unit Ob. $8.33 per unit Oc. $0.58 per unit Od. $0.12 per unit