Manisha Inc. manufactures Wifi speakers designed for boardrooms using streaming videos. From the list provided, identify all costs that would be recorded as a product cost.

1) Plant manager's salary 2)Cost of heating the plant 3)Cost of heating the executive offices. 4) Salaries and commissions of company salespersons 5) Wages of janitorial personnel who clean the plant 6) Cost of insurance on the plant building 7)Cost of printing promotional materials for trade shows. 8) Cost of printed circuit boards used in the Wifi speakers.