Which of the following is considered an operating expense?

Operating expenses are the costs that a company incurs through its normal business operations. They are essential for the day-to-day functioning of the business but are not directly tied to the production of goods or services.

Salaries of employees fall under this definition because they represent compensation for work performed as part of the ongoing operations of the business. This includes wages, benefits, and payroll taxes associated with employees who are critical to the company's routine operations. These costs are necessary for maintaining business activities and supporting production or service delivery.

In contrast, the cost of raw materials, interest on loans, and the purchase of new machinery do not qualify as operating expenses. The cost of raw materials is classified as a cost of goods sold, which pertains to production rather than operational overhead. Interest on loans is typically considered a financial expense, reflecting costs related to financing rather than day-to-day operations. The purchase of new machinery is recorded as a capital expenditure, reflecting a long-term investment rather than an operating cost. Therefore, salaries of employees is the correct answer as it directly supports the ongoing operational capabilities of a business.