A composite rod made of copper ($\mathrm{\alpha }$ = 1.8 x 10^-5 K^-1) and steel ($\mathrm{\alpha }$ = 1.2 x 10^-5 K^-1) is heated, then it:

• A

  bends with steel on concave side

• B

  bends with copper on concave side

• C

  does not expand
   

• D

  data is insufficient