Calculate the thermal stress developed if the specification of a rod are given

Question

A steel rod 10 min in diameter and 1 m long is heated from 20⁰C to 120⁰C, E = 200 GPa and  

$\alpha$ = 12 x 10^-6 per ⁰C. If the rod is not free to expand the thermal stress developed is

(a) 120 MPa (tensile)                  (b) 240 MPa (tensile)   

(c) 120 MPa (compressive)         (d) 240 MPa(compressive)