A steel has its yield strength of 200N/mm2 and modulus of elasticity of 1x105MPa. Assuming the material to obey hookes law up to yielding, what will be its proof resilience?

• A. 0.8 N/mm2
• B. 0.4 N/mm2
• C. 0.2 N/mm2
• D. 0.6 N/mm2