In a square beam loaded longitudinally, shear develops
(A) On middle fibre along horizontal plane
(B) On lower fibre along horizontal plane
(C) On top fibre along vertical plane
(D) Equally on each fibre along horizontal plane
(A) On middle fibre along horizontal plane
(B) On lower fibre along horizontal plane
(C) On top fibre along vertical plane
(D) Equally on each fibre along horizontal plane