Final answer:
The correct engineering control installed to mitigate fall hazards from the given options is a) Guardrail System. It is designed to prevent employees from falls and is considered a passive form of protection that requires no action from the employee to be effective.
Step-by-step explanation:
An engineering control installed to mitigate fall hazards is a system specifically designed to prevent employees from falling off, onto, or through working levels and to protect them from being struck by falling objects. Among the options provided, the correct one that fits the definition of an engineering control is:
Guardrail System
Guardrail systems are a form of passive protection that do not require the employee to wear or do anything to be protected; they are built into the workplace. Guardrails are barriers erected to prevent employees from falling to lower levels, thus mitigating fall hazards. In comparison, the personal fall arrest system, safety net, and warning sign are not considered engineering controls. A personal fall arrest system is personal protective equipment that stops a person amid a fall. A safety net is used to catch falling people and thereby reduce the risk of serious injury. Lastly, a warning sign only alerts to the potential of a hazard but does not control or eliminate the hazard itself. Therefore, in the context of fall hazard mitigation within the workplace, an engineering control refers to any physical change to the workplace that eliminates or reduces the risk of a fall without requiring additional actions by the workers, such as the installation of guardrails systems.