The symmetric equation of a straight line passing through two points \( (x_1, y_1, z_1) \) and \( (x_2, y_2, z_2) \) is given by:
\[
\frac{x - x_1}{x_2 - x_1} = \frac{y - y_1}{y_2 - y_1} = \frac{z - z_1}{z_2 - z_1}
\]
Substituting the given points, we obtain:
\[
\frac{x+1}{-2} = \frac{y-4}{-4} = \frac{z-2}{3}
\]
Thus, the correct answer is (C).