83. Which of the following is an example of a cost that varies in total as the number of units produced changes? a. salary of a production supervisor b. direct materials cost c. property taxes on factory buildings d. straight-line depreciation on factory equipment 84. Which of the following is not an example of a cost that varies in total as the number of units produced changes? a. electricity per KWH to operate factory equipment b. direct materials cost c. straight-line depreciation on factory equipment d. wages of assembly worker 85. Which of the following is not an example of a cost that varies in total as the number of units produced changes? a. electricity per KWH to operate factory equipment b. direct materials cost c. insurance premiums on factory building d. wages of assembly worker