The angle between two vectors $\overrightarrow{A}$ and $\overrightarrow{B}$ is $\theta$ . Resultant of these two vectors is $ \overrightarrow{R}$ Which makes an angle of $\large\frac{\theta}{2}$ with $\overrightarrow{A}$. Which of the following is true?

Question

$\begin{array}{1 1}(A)\;A=2B \\(B)\;A=B \\(C)\;B=2A\\(D)\;A= 1/B \end{array} $