Ductility is the mechanical property that lets a material undergo large plastic (permanent) deformation under tensile stress, so it can be pulled and stretched into thin wires without fracturing. This is exactly what happens in the industrial wire-drawing process, where a metal rod is pulled through progressively smaller dies to form fine wire.

This is why conductors such as copper and aluminium — both highly ductile — are the standard choice for electrical wiring: they can be drawn into long, thin, flexible strands that still carry current reliably.

Why the other properties do not fit:

• Elasticity is only the ability to return to the original shape after the load is removed; it describes recoverable deformation, not the permanent stretching needed to form a wire.
• Hardness is resistance to surface scratching or indentation — useful for cutting tools, but unrelated to being drawn into wire.
• Brittleness is effectively the opposite of what is required: a brittle material (like glass or cast iron) fractures suddenly with almost no plastic deformation, so it would snap during drawing.

A closely related but distinct term is malleability, the ability to be hammered or rolled into thin sheets under compression; drawing into wires under tension is specifically ductility.