A beam of light from a source L is incident normally on a plane mirror fixed at a certain distance x from the source. The beam is reflected back as a spot on a scale placed just above the source L. When the mirror is rotated through a small angle $$\theta$$, the spot of the light is found to move through a distance y on the scale. The angle $$\theta$$ is given by

A

$$\frac{x}{2y}$$

B

$$\frac{x}{y}$$

C

$$\frac{y}{2x}$$

D

$$\frac{y}{x}$$