Final answer:
The recommended force for pushing or pulling open doors (other than fire doors) is 5 pounds of force, to meet accessibility guidelines.
Step-by-step explanation:
The question refers to the recommended force for pushing or pulling open doors, which is not directly related to the physics calculations provided in the reference. However, life safety codes and Americans with Disabilities Act (ADA) regulations suggest that the force to open doors (not including fire doors) should not exceed 5 pounds of force (22.2 N) to ensure accessibility for people with disabilities. This makes option a) the correct answer.