A rectangular steel bar, which is of 2.8 m long and 15 mm thick, is subjected to an axial tensile load of 40 kN. If width of the bar varies from 75 mm at one end to 30 mm at the end, then what is the extension of the bar if E = 2 x 106 N/mm2?

• A. 0.86 mm
• B. 0.36 mm
• C. 0.76 mm
• D. 0.50 mm