Glory Industries manufactures brass trumpets. Glory manufactured 3,000 trumpets in April and 3.900 trumpets in May. Here are data regarding Glory's manufacturing costs: Manufacturing cost 1. Electricity used to run machinery and equipment 2. Sheets of brass (raw material) 3. Valves purchased from suppliers (component parts) 4. Wages of factory workers, including supervisors April $87,000 $40,000 $165.000 $207,000 May S101,600 S52,000 $214,500 S236,000 Which costs are properly classified as mixed costs Only 1 Only 1 and 4 Only 2 and 3 0.Only 3 and 4 Only 4