What must be provided underground at all branch circuits extending from primary power circuits near shafts?

The correct choice emphasizes the necessity of disconnecting switches at all branch circuits extending from primary power circuits near shafts. These switches are critical safety devices that allow for the safe isolation of electrical power when maintenance or emergency work is required.

In the context of underground mining operations, where conditions can be hazardous and the risk of electrical accidents is significant, having readily accessible disconnecting switches is essential to ensure workers can quickly cut off power in emergencies. This not only helps in protecting the personnel working in those areas but also prevents potential electrical hazards that could lead to fires or equipment damage.

Other options, while they may serve important roles in a mining environment, do not specifically address the immediate need for safely managing electrical power in proximity to primary circuits. Control panels are crucial for controlling circuits, warning lights are used for signaling potential hazards, and first aid kits are essential for medical emergencies but do not have the same immediate safety application regarding electrical disconnections as disconnecting switches do.