A composite department is a fire department that is:

A composite department is characterized by its staffing structure, which includes both full-time firefighters and on-call or part-time firefighters. This blend allows the department to maintain a higher level of readiness and availability while managing costs. The combination of full-time personnel provides the consistency and advanced training needed for complex fire response situations, while on-call firefighters can supplement staffing, particularly in areas with fluctuating demand for services. This model enhances the overall operational capacity of the fire department and serves communities effectively by ensuring that a diverse pool of personnel is available for various emergency scenarios.

The other options describe different organizational structures or funding models but do not accurately define what a composite department entails. For example, staffing exclusively with volunteers or focusing solely on private funding does not fit the definition of a composite department as it relies heavily on a combination of staffing types, which is essential to its operational strategy.