A steel rod, 2m long, is held between two walls and heated from $20_{}^{0}\textrm{C}$ to $60_{}^{0}\textrm{C}$. Young’s modulus and coefficient of linear expansion of the rod material are $200\times 10^{3}MPa$ and $10\times 10^{-6}/_{}^{0}\textrm{C}$ respectively. The stress induced in the rod, if walls yield by 0.2mm, is
(a) 60 MPa tensile
(b) 80 MPa tensile
(c) 80 MPa compressive
(d) 60 MPa compressive