The curved surface of uniform rod is thermally isolated from surrounding. Its ends are maintained at temperature $T_{1}$ and $T_{2}\left(T_{1}>T_{2}\right) .$ If in steady state, temperature gradient at a distance $x$ from hot end is equal to $\frac{d T}{d x}$, then which one of the following graphs is correct?
(A)
(B)
(C)
(D)