Where is the assist space for the N4?

The assist space for the N4 is correctly identified as being located at R1 beside the R1 door frame, facing the aft of the aircraft. This arrangement provides crew members with immediate access to assist passengers in case of an emergency and ensures that the space is optimally positioned to support efficient evacuation procedures.

In the context of this question, the assist space's placement is vital for safety considerations, as it allows for quick access to assist those in need while also facilitating the smooth operation of crew duties during boarding and deplaning. Understanding the precise locations of assist spaces on the aircraft is important for effective training and readiness in emergency situations.

The other options do not accurately describe the assist space for the N4. The specific locations and orientations must align with practical operational contexts, which points to option B as the correct choice.