(c)
Slope of given line is $\frac{1}{\sqrt{3}}$ , it’s angle from positive $x$-axis is $30{^\circ}$ . Now, lines making an angle $30{^\circ}$ from it are either $x$-axis $(ie,\ y = 0)$ or makes and angle $60{^\circ}$ with positive $x$-axis $\left( ie,\ y = \sqrt{3}x + \lambda \right)$