A company incurs the following operating expenses in a given period Expenses April May June Advertising expense 5,000 5.000 5,000 Shipping expense 67,500 75,600 72,000 Salaries commissions 30,800 34,400 32,800 Insurance 4,000 4,000 4,000 Depreciation 2,500 2,500 2,500 Advertising is an example of PLEASE REFER TO Question 15 O Variable cost Mixed cost Fixed cost O None of the above