Final answer:
When a travel restraint system is not feasible, a fall arrest system should be implemented as an alternative method of fall protection, ensuring worker safety according to occupational health and safety standards.
Step-by-step explanation:
When the use of a travel restraint system cannot be used for a given situation, an alternative fall protection method should be: A) Fall arrest system. This is because when restraint systems, which prevent workers from reaching a point where a fall could occur, are not feasible, a fall arrest system is designed to stop a fall in progress and minimize the impact of the fall. Other options like safety net systems or warning line systems may also be considered depending on the specific work environment and hazards present. It is imperative that whatever method chosen, it adheres to occupational health and safety standards to ensure worker safety.