Primary Health Care structure in India:PHC provides two broad categories of services: (1) Preventive and (2) Curative. The Preventive arm is further split into General Services and Care of Vulnerable Groups.
Care of Vulnerable Groups (at PHC level) includes:- Maternal & Child Health services
- School Health Services
- Geriatric Health Services
- Occupational Health Services
Since school health service is listed under the PHC-level preventive services for care of vulnerable groups, the correct level is PHC -- not Sub-centre, Sub-district, or District.
\[\boxed{\text{PHC (Primary Health Centre)}}\]
