Which CRJ exit has a window on it?

The correct answer identifies the Ground Service Door (GSD) as having a window. The GSD is typically located on the left side of the aircraft and serves multiple purposes, including providing access for maintenance personnel and servicing the aircraft while on the ground. The presence of a window on the GSD aids in visibility, allowing ground crews to monitor the status of tasks being performed in and around the door.

The other options do not feature a window. The Main Cabin Door (MCD) is designed primarily for passenger entry and does not include a window; it is a robust, secure entrance for boarding. The crew escape hatch provides an emergency exit for the crew but, similar to the MCD, is not equipped with a window. Over-wing exits are designed for passenger evacuation and also lack windows, being built for functionality during an emergency rather than visibility.

In summary, the GSD stands out for having a window, enhancing the utility and visibility for ground operations, while the other exits prioritize secure access and emergency readiness without a visual component.