(A) : When temperature difference across the two sides of a wall is increased, in steady state, its temperature gradient increases.
( R) : Thermal conductivity linearly depends on temperature difference between the ends.

Options

A. Both (A) and (R) are true and (R) is the correct explanation of (A)
B. Both (A) and (R) are true and (R) is not the correct explanation of (A)
C. (A) is true but (R) is false
D. Both (A) and (R) are false

Answer

C