Rails are laid such that there will be no stress in them at 24°C. If the rails are 32 m long with an expansion allowance of 8 mm per rail, coefficient of linear expansion a = 11´10–6/°C and E = 205 GPa, the stress in the rails at 80°C will be nearly

• A. 68 MPa
• B. 75 MPa
• C. 83 MPa
• D. 90 MPa