The horizontal area of the window well of the emergency escape and rescue opening should be at least ___ square feet.

The horizontal area of the window well for emergency escape and rescue openings is established to ensure that individuals can safely exit a building in case of an emergency. A minimum area of at least 9 square feet is required to provide sufficient space for individuals to exit easily while also allowing for adequate visibility and ventilation. This size is designed to accommodate common escape scenarios and ensure overall safety.

Options that specify either smaller or larger areas do not meet the established code requirements; hence, they are considered non-compliant. The choice of 9 square feet strikes a balance between safety and practicality, making it the correct answer in this context.