Which of the following represents direction cosines of the line?

Correct option is B

​$$\begin{aligned}&\text{Direction cosines } l, m, n \text{ of a line must satisfy the condition:} \\&\quad l^2 + m^2 + n^2 = 1 \\\\&\text{So, for each option, we compute:} \\&\quad l^2 + m^2 + n^2 \\&\text{Only the one that gives 1 will be the valid set of direction cosines.} \\\\&\text{\underline{Option B:}} \\&\quad l = 0, \quad m = \frac{\sqrt3}{2}, \quad n = \frac{1}{2} \\&\quad 0^2 + \left( \frac{\sqrt3}{2} \right)^2 + \left( \frac{1}{2} \right)^2 = \frac{3}{4} + \frac{1}{4} = \frac{4}{4} = 1 \\\end{aligned}$$​​