As x increases, the state temperature gradient (dT/dx) will

Question

Consider one-dimensional steady state heat conduction, without heat generation, in a plane wall; with boundary conditions as shown in the figure below. The conductivity of the wall is given by k=k₀+bT; where k₀ and b are positive constants, and T is temperature                                                                                             

As x increases, the state temperature gradient (dT/dx) will

      (a) remain costant                                               (b) be zero

      (c) increase                                                         (d) decrease