During preflight checks, what indicates that the escape slide is ready for deployment on the ERJ 175?

The indication that the escape slide is ready for deployment on the ERJ 175 is marked by the gauge needle being in the green zone. This green zone signifies that the system is properly pressurized and functioning correctly, thus ensuring that the escape slide can be deployed in the event of an emergency. It is important for the crew to check this indicator during preflight checks to confirm that safety equipment is operational and ready for any unexpected situations.

The other options typically signify issues or different conditions; for instance, a red indicator light generally highlights a problem or malfunction, while a green indicator light would not directly apply to the escape slide's readiness. A pressure gauge needle in the yellow zone indicates caution or a suboptimal pressure level, suggesting that the escape slide may not be fully ready for deployment. Therefore, the gauge needle being in the green zone directly correlates with the proper operational status of the escape slide system.