Two coherent sources of light $$S_1$$ and $$S_2$$, equidistant from the origin, are separated by a distance $$2\lambda$$ as shown. They emit light of wavelength $$\lambda$$. Interference is observed on a screen placed along the circle of large radius $$R$$. Point P is seen to be a point of constructive interference. Then, angle $$\theta$$ (other than $$0^\circ$$ and $$90^\circ$$) is

A

$$45^\circ$$

B

$$30^\circ$$

C

$$60^\circ$$

D

not possible in the first quadrant