Which of the following is a key resource in combating onboard fires?

Firefighting equipment is an essential resource for combating onboard fires because it is specifically designed and engineered to suppress and extinguish flames. This equipment includes items such as fire extinguishers, hoses, fire axes, and other tools that are critical during a fire response. Utilizing the right firefighting equipment allows personnel to quickly and effectively tackle fires before they escalate, thereby ensuring the safety of the crew and the vessel.

In contrast, navigation charts are primarily used for route planning and safe passage at sea, while lifesaving equipment is designed for rescue situations and ensuring survival in emergencies, such as life jackets and lifeboats. Entertainment systems, although important for morale and recreational purposes, do not contribute to fire safety or firefighting efforts. The focus of keeping the ship and its personnel safe during a fire incident is paramount, making firefighting equipment the key resource in such scenarios.