Q. According to Rankine's theory, the failure occurs at a point in a member

(A) When the maximum shear stress in a biaxial stress system reaches the shear stress at elastic limit in a simple tension test

(B) When the maximum principal stress in a biaxial stress system reaches the elastic limit of the material in a simple tension test

(C) When the strain energy per unit volume in a biaxial stress system reaches the strain energy at the elastic limit per unit volume as determined from a simple tension test

(D) When the maximum principal strain in a biaxial stress system reaches the strain at the elastic limit as determined from a simple tension test