A good lubricant should have

The correct option is High viscosity.

A lubricant is a substance introduced between two moving surfaces to reduce friction, wear, and the generation of heat. One of the most critical properties of a lubricant is its viscosity.

Viscosity is defined as a fluid's resistance to gradual deformation by shear or tensile stress (informally, its "thickness"). A good lubricant should possess a high viscosity (under operating conditions) for several reasons:
1. Formation of a Protective Film: A high-viscosity lubricant can form a sufficiently thick and continuous hydrodynamic film between the moving components. This film prevents direct metal-to-metal contact, thereby reducing wear and friction.
2. Load-Carrying Capacity: Viscous fluids can withstand high pressures and heavy loads without being squeezed out from the contact zone.
3. Temperature Resistance: Viscosity decreases as temperature increases. Starting with a higher viscosity ensures that even when the operating temperature rises, the lubricant will retain enough thickness to keep the surfaces separated.