Q. In the calculation of induced shear stress in helical springs, the Wahl's stress factor is used to take care of

• (A) Combined effect of transverse shear stress and bending stress in the wire
• (B) Combined effect of bending stress and curvature of the wire
• (C) Combined effect of transverse shear stress and curvature of wire
• (D) Combined effect of torsional shear stress and transverse shear stress in the wire