If,with Steady State Thermal Energy Flow Established,you Double the Thickness $\sqrt { 2 }$

If,with steady state thermal energy flow established,you double the thickness of a wall built from solid uniform material,the rate of thermal energy transfer our of the room for a given temperature difference across the thickness will

A) become one-half its original value.
B) also double.
C) become one-fourth its original value.
D) become 1/ $\sqrt { 2 }$ of its original value.
E) become four times its original value.