Concept:Stress is defined as the force applied per unit cross-sectional area of a wire.Explanation:Given diameter D=πym and the load is the weight F=y2N.Radius is half the diameter: r=2D=2πym.Cross-sectional area of the wire: A=πr2=π(2πy)2=4πy2m2.Now, stress = AF.Substitute the values: Stress=y2/(4π)y2=4πNm−2.Thus, the wire experiences a stress of 4πNm−2.Answer:4πNm−2 (Option C).