Two ends of a conducting rod of varying cross-section are maintained at `200^(@)C` and `0^(@)C` respectively. In steady state:
A. temperature differences across `AB and CD` are equal
B. temperature difference aross `AB` is greater than that across `CD`
C. temperature difference aross `AB` is less than that across `CD`
D. temperature difference may be equal or different depending upon thermal conductivity of the rod.