Which of the following stresses are associated with the tightening of nut on a bolt.
1. Tensile stress due to stretching of bolt.
2. Bending stress due to the bending of bolt.
3. Crushing and shear stress in thread.
4. Torsional shear stress due to frictional resistance between the nut and the bolt.
(a) 1,2 and 4 (b) 1,2 and 3
(c) 2,3 and 4 (d) 1,3,4 only