Correct option is D
Rigid pavements are typically analyzed using elastic theory, not plastic theory. The assumption is that the pavement is resisting over an elastic foundation & stress analysis is based on this principle.
Rigid pavements do not get deformed to the shape of the supporting layer below it. Rigid
pavements are designed to be stiff & resist deformation, not like flexible pavements.
Flexible pavements can experience both permanent (non-recoverable) & temporary (recoverable) deformations due to the traffic loads & environmental factors. These deformations can manifest as cracks, rut- ting & other surface distresses.
