In terms of service listing, what does a service need to qualify as supportive?

To qualify as supportive, a service must enhance the effectiveness of primary services. This means that supportive services provide additional benefits or resources that complement the main services being offered, leading to improved outcomes for clients. For instance, in a healthcare context, supportive services like counseling or transportation can significantly improve a patient's ability to access and benefit from their primary medical services.

In contrast, the other choices do not capture the essence of what makes a service supportive. Having a dedicated funding source, while important for sustainability, does not inherently relate to the service's supporting role. Similarly, the necessity for primary function suggests that the service is critical, rather than enhancing existing services. Lastly, the frequency of client requests could indicate demand but does not define the supportive nature or effectiveness of the service in relation to primary services. Therefore, the focus on enhancing efficacy illustrates why the correct answer is the most accurate representation of a supportive service criterion.