At a height 0.4 m from the ground the velocity of particle projected in angle $\theta$ is $\hat v=(6 i+ 2 j)m/s$ The angle of projection $\theta$ is $(g=10 m/s^2)$

Question

$$(a)\;45 ^{\circ}\quad (b)\;30 ^{\circ} \quad (c)\;60^{\circ} \quad (d)\tan ^{-1} \frac{3}{4}$$