What is included in the No4 Cabin secure checks?

The correct choice identifies the specific areas that need to be secured and checked for safety within the No4 cabin structure during flight operations. In this context, the FWD toilet is an important area as it is frequently used and can be a point of concern for safety. Additionally, securing the area to No1 indicates that the cabin crew must ensure that this section, extending up to the front of the aircraft, is safe and secure, preventing unauthorized access and ensuring all safety protocols are adhered to.

This comprehensive check is critical in maintaining the safety and security of passengers and crew on board, particularly in high-density or busy cabins. It reflects standards that emphasize on thoroughness in safety measures, specifically related to passenger areas and crew-accessible sections. Each of the other options does not cover these critical areas or has defined limits that do not align with comprehensively securing the No4 cabin.