If vectors $\overrightarrow{A} = \cos wt \hat i +\sin w + \hat j$ and $\overrightarrow{B} = \cos wt/2 \hat i +\sin wt/2 + \hat j$ are functions of time , then the value of t at which are orthogonal to each other is

Question

$\begin{array}{1 1} t= \frac{\pi}{w} \\ t=0 \\ t= \frac{\pi}{4w} \\ t= \frac{\pi}{2w} \end{array}$