Linear Materials Operate According to Hooke's Law, Which Means That

Linear materials operate according to Hooke's Law, which means that ____________.

A) stress and strain are non-linearly related such that resulting strain is proportional to the developed stress
B) they do not experience energy loss once a load is removed from the material
C) once a load is removed from the material a permanent set remains because the material has entered the region of plastic deformation
D) where stress and strain are linearly related such that the resulting strain is inversely proportional to the developed stress