Mark (√) against the correct answer in the following: If $\mathrm{f}(\mathrm{x})=\frac{(4 \mathrm{x}+3)}{(6 \mathrm{x}-4)}, \mathrm{x} \neq \frac{2}{3}$ then $(\mathrm{f} \circ \mathrm{f})(\mathrm{x})=?$ A. $x$ B. $(2 x-3)$ C. $\frac{4 x-6}{3 x+4}$ D. None of these