Assertion (A) and Reason (R)
(A) Both A and $\mathrm{R}$ are true and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
(B) Both $\mathrm{A}$ and $\mathrm{R}$ are true but $\mathrm{R}$ is not the correct explanation of $\mathbf{A}$.
(C) $\mathrm{A}$ is true, $\mathrm{R}$ is false.
(D) $\mathrm{A}$ is false, $\mathrm{R}$ is true.
Assertion $(\mathrm{A}): \mathrm{A}$ tangent parallel to $\mathrm{x}$-axis can be drawn for $f(x)=(x-1)(x-2)(x-3)$ in the interval $[1,3]$ Reason (R): A horizontal tangent can be drawn to any cubic function.