Cashion Company produces chemical mixtures for pharmaceutical companies. Its factory has four mixing lines that mix chemical powders. Each line can produce up to 5,000 barrels per year. Each line needs one supervisor who is paid $34,000 of salary per year. If the companys normal operating (relevant) range is 16,000 to 19,000 barrels per year, how would the company consider the cost of salaries paid to supervisors? Group of answer choices

Step cost

Mixed cost

Fixed cost

Variable cost