In a scattering experiment, a particle of mass $$2m$$ collides with another particle of mass $$m$$, which is initially at rest. Assuming the collision to be perfectly elastic, the maximum angular deviation $$\theta$$ of the heavier particle, as shown in the figure, in radians is:

A

$$\pi$$

B

$$\tan^{-1}\left(\frac{1}{2}\right)$$

C

$$\frac{\pi}{3}$$

D

$$\frac{\pi}{6}$$