Due to the pure bending deformation, the longitudinal ( ) strain varies ( ) from ( ) at the neutral axis to a maximum at the outer fibers of the beam. A: normal; linearly; zero B: shear; nonlinearly; zero C: shear; nonlinearly; zero D: shear; nonlinearly; zero

When a shaft having a circular cross section is subjected to a torque, the cross section remains plane while radial lines rotate. This causes a ( ) within the material that varies ( ) along any ( ) line. A: shear strain; linearly; radial B: normal strain; linearly; radial C: shear strain; nonlinearly; radial D: shear strain; nonlinearly; longitudinal