Carl purchased the following assets during the tax year for use in his sole proprietorship: January 6 Equipment $7,400 October 12 Truck 20,000 December 1 Machinery 2,000 Which of the following statements is true? Carl must use half-year convention for the equipment; and must use mid-quarter convention for the truck and machinery Carl must use mid-quarter convention for all assets purchased during the year Carl must use mid-quarter convention for the equipment; and must use half-year convention for the truck and machinery Carl must use half-year convention for all assets purchased during the year Carl can use any convention he wants for any of the assets