Stony Electronics Corporation manufactures a Wifi speaker designed for mounting on the wall of the bathroom. The following list represents some of the different types of costs incurred in the manufacture of these Wifi speakers: 1) The plant manager's salary. 2) The cost of heating the plant. 3) The cost of heating executive offices. 4) The cost of printed circuit boards used in the Wifi speakers. 5) Salaries and commissions of company salespersons. 6) Depreciation on office equipment used in the executive offices. 7) Depreciation on production equipment used in the plant. 8) Wages of janitorial personnel who clean the plant. 9) The cost of insurance on the plant building. 10) The cost of electricity to light the plant. 11) The cost of electricity to power plant equipment. 12) The cost of maintaining and repairing equipment in the plant. 13) The cost of printing promotional materials for trade shows. 14) The cost of solder used in assembling the Wifi speakers. 15) The cost of telephone service for the executive offices. Required: Classify each of the items above as product (inventoriable) cost or period (non-inventoriable) costs for the purpose of preparing external financial statements.