If the rigid rod fitted snugly between the supports as shown in the figure below, is heated, the stress induced in it due to $20^{0}C$ rise in temperature will be $(\alpha = 12.5\times 10^{-6}/_{}^{0}\textrm{C})$ $and E=200GPa)$
(a) 0.07945MPa (b) -0.07945MPa
(c) -0.0397MPa (d) 0.03972MPa