Correct choice is (d) Spheroidise annealing
Easy explanation: Stress relief annealing is carried out to remove the stresses caused by castings, quenching, machining, welding etc. This can be done by prolonged heating of the material slightly above and below the A1 line. Full annealing occurs above the A1 and A3 lines, whereas process annealing occurs slightly below the A1 line.