Correct option is (d) elongation on standard gauge length should be more than 15%
Easiest explanation: The conditions that stress strain characteristics of steel should obey to ensure plastic moment redistribution are: (i) yield plateau(horizontal portion of stress strain curve) should be greater than 6 times the yield strain, (ii) ratio of ultimate tensile stress to yield stress should be more than 1.2, (iii) elongation on standard gauge length should be more than 15%, (iv) steel should exhibit strain-hardening capacity.