Which entity is responsible for the oversight of Guam's public health?

The Guam Department of Public Health and Social Services is the correct answer as it is the primary agency tasked with overseeing public health in Guam. This department is responsible for implementing health policies, managing public health programs, and ensuring the overall health and welfare of the population. It encompasses various divisions focused on health promotion, disease control, and environmental health, which are essential for maintaining public health standards and addressing health concerns in the community.

The other entities listed have different functions that do not primarily relate to the general oversight of public health in Guam. For instance, the Guam Health Department may refer to more generalized health initiatives without the comprehensive scope covered by the Department of Public Health and Social Services. The Guam Health Authority, while involved in some health regulatory functions, does not have the same broad mandate as the Department of Public Health and Social Services. Similarly, the Guam Department of Welfare focuses more on social services rather than public health, making it less relevant to this particular question.