Which component must be pressed to provide power from the house batteries to the engine?

The component that must be pressed to provide power from the house batteries to the engine is the Emergency Boost button. This button is specifically designed to connect the house batteries to the engine's starting system in situations where the engine's primary starting batteries may be low or depleted. Activating the Emergency Boost allows for a temporary power source to assist with starting the engine, ensuring that the vessel can operate safely, especially in critical situations.

This functionality is vital for maintaining control and reliability in marine operations, particularly during rescue missions or emergencies when immediate engine power is necessary. The other components serve different purposes, such as starting the engine or controlling the ignition system, but they don’t facilitate the connection between the house batteries and the engine in the same way as the Emergency Boost button does.