Which of the following stresses are associated with the tightening of nut on a bolt? (1) Tensile stress due to the stretching of bolt (2) Bending stress due to the bending of bolt (3) Crushing and shear stresses in threads (4) Torsional shear stress due to frictional resistance between the nut and the bolt. Select the correct answer using the codes given below:

• A. 1, 2 and 4   
• B. 1, 2 and 3   
• C.  both [a] and [b]
• D. 1, 3 and 4