Olivine Refrigerators has 12 sales representatives, each earning a salary of $43,000 per year plus a commission of $18 per refrigerator sold. If 31,000 refrigerators are sold, then the total cost associated with the sales representatives is: O a. $1,074,000. O b. $1,290,000. c. $558,000. O d. $516,000. Which of the following is an example of a discretionary fixed cost? O a. Lease installment Ob. Advertising cost c. Depreciation on an office building O d. Property tax A cost that is variable in nature but whose rate of change is not constant is called a: O a semi-variable cost. O b. committed variable cost. O c. relevant variable cost. O d. discretionary variable cost. For planning and control purposes, O a. mixed costs should be ignored O b. mixed costs should be considered sunk costs c. only the fixed component of mixed costs should be considered O d. mixed costs should be separated into variable and fixed components