The greatest load which a spring can carry without getting permanently distorted, is called A. Stiffness B. Proof resilience C. Proof stress D. Proof load

Stiffness is the resistance of an object to deformation under an applied force. It is a measure of how difficult it is to deform an object.

Proof resilience is the ability of a material to absorb energy without permanent deformation. It is a measure of how much energy a material can absorb before it is permanently deformed.

Proof stress is the stress at which a material begins to deform permanently. It is a measure of the strength of a material.