Assertion (A) : Equation of a line passing through the points $(1, 2, 3)$ and $(3, -1, 3)$ is $\frac{x - 3}{2} = \frac{y + 1}{3} = \frac{z - 3}{0}$. Reason (R) : Equation of a line passing through points $(x_1, y_1, z_1)$, $(x_2, y_2, z_2)$ is given by $\frac{x - x_1}{x_2 - x_1} = \frac{y - y_1}{y_2 - y_1} = \frac{z - z_1}{z_2 - z_1}$.