What force must guardrails withstand according to safety regulations?

The correct answer reflects the safety regulations governing the required strength of guardrails, specifically the amount of force that should be applied to the top rail. Guardrails are designed to ensure safety by preventing falls from elevated areas. Safety standards, such as those from the Occupational Safety and Health Administration (OSHA), stipulate that the top rails of guardrails must be able to withstand a force of at least 200 pounds applied in a downward or outward direction.

This specification is intended to ensure that the guardrail system can effectively prevent a person from falling in case they accidentally lean against or push against the rail, ensuring a higher level of safety in environments where individuals might be at risk of falling from heights. The other provided choices do not meet the standard force requirement set for the top rail of guardrails, indicating that they would not provide adequate safety protection. Thus, the requirement of 200 pounds for the top rail is essential for compliance with safety norms and for maximizing user safety.