A thin rod of length '$$L$$' is lying along the $$x$$-axis with its ends at $$x = 0$$ and $$x = L$$. Its linear density (mass/length) varies with $$x$$ as $$k\left(\frac{x}{L}\right)^n$$, where $$n$$ can be zero or any positive number. If the position $$x_{CM}$$ of the centre of mass of the rod is plotted against '$$n$$', which of the following graphs best approximates the dependence of $$x_{CM}$$ on $$n$$?