Which of the following is classified as a Personal Service?

The classification of "Personal Service" refers to expenses that are directly related to paying individuals for their labor or services. In this context, salaries and wages represent direct compensation for work performed by employees. This includes both regular salaries and hourly wages for the staff, which directly contribute to the operation of an organization or institution.

The other options – supplies and materials, office equipment, and utilities – do not fall under the category of personal services. Supplies and materials are consumables used in the daily operation of a business or organization, while office equipment refers to physical assets necessary for the operation, such as computers and printers. Utilities encompass services like electricity and water, which are necessary for maintaining a functional environment but do not involve direct compensation for personal labor. Thus, the correct answer is indeed salaries and wages, as this is the only option that reflects direct payment for personal services rendered.