Final answer:
Health psychologists focus on studying the impact of psychological factors on healthcare access and delivery, which is central to analyzing health care systems and formulating health policy.
Step-by-step explanation:
Health psychologists study how psychological factors influence healthcare access and delivery to analyze the healthcare system and formulate health policy. Choice C, the impact of psychological factors on healthcare access and delivery, is the focus of health psychology. These professionals may investigate the complex interplay between genetic makeup, behavior, psychological stress, relationships, and health. They are particularly interested in understanding how these factors contribute to health outcomes and how interventions can be tailored to improve public health. Through their research and application of the biopsychosocial model, health psychologists aim to design public policies and interventions that promote better health outcomes and address disparities in healthcare access. They also delve into how broader structural differences in healthcare systems, like those between publicly funded and privately funded healthcare, can affect individual and population health.