Which of the following best describes overhead costs?

Overhead costs are best described as those expenses associated with the general operation of a business that cannot be directly attributed to specific products or services. This includes costs such as rent, utilities, salaries of administrative staff, and office supplies. These expenses are necessary for maintaining the business's infrastructure and supporting production, but they do not vary directly with production levels or specific sale items.

This definition highlights that overhead costs play a crucial role in the overall budgeting and financial health of a business, as they must be managed carefully to ensure sustainability. The other options fail to capture this essence: direct expenses relate specifically to goods or services, variable costs fluctuate with production volumes, and one-time expenses pertain solely to startup costs rather than ongoing operational expenditures.