Lifelines used in areas where they may be subjected to cutting or abrasion must be a minimum of what size in rope?

Lifelines that are subject to cutting or abrasion must have sufficient strength and durability to ensure safety for individuals using them in potentially hazardous environments. The minimum specified size of 7/8" wire-core manila rope is designed to provide enhanced resistance to wear and damage. The wire core adds tensile strength, making it less prone to fraying and breaking under tension, which is crucial in scenarios where the rope might be exposed to sharp edges or abrasive surfaces.

This specific size and material combination ensure that the lifeline can withstand the rigors of construction or industrial environments, where safety is paramount. The other options, while they may be strong in different contexts, lack the necessary properties or size to effectively serve as a lifeline in conditions where cutting or abrasion might occur.