Which document serves as the legal basis for the implementation of Primary Health Care (PHC) in the Philippines?

The legal foundation for the implementation of Primary Health Care (PHC) in the Philippines is rooted in specific legislative documents that outline the framework and objectives for health care delivery. Among the options provided, the most relevant document is the Letter of Instruction. This document plays a pivotal role in establishing the policies and directives for the PHC approach, emphasizing its importance in ensuring equitable access to health services across the nation.

The Letter of Instruction outlines the government's commitment to health care reforms, focusing on community involvement, disease prevention, and broader access to health services, which are all core principles of PHC. By setting these directives, the Letter guides health care practices and helps in the allocation of resources, aligning with the goals of improving public health and enhancing health care systems throughout the country.

While the other legislative acts also pertain to health care in various capacities, they do not specifically serve as the foundational legal document for the implementation of the PHC model.