A beam is loaded by couples at each of its ends, the magnitude of each couple being 5 kN-m. The beam is of steel and its cross- section is shown in figure. The maximum tensile stress in the beam, in MPa, is 5 kN-m (a) 18.3 (c) 55 5 kN-m 84.7 mm NA 40.3 mm INA 7.7106 mm 01 (b) 26.2 (d) 74.32