If $$\theta_1 and \theta_2$$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip $$\theta$$ is given by

A

$$\cot^2 \theta = \cot^2\theta_1 - \cot^2\theta_2$$

B

$$\tan^2 \theta = \tan^2\theta_1 - \tan^2\theta_2$$

C

$$\cot^2 \theta = \cot^2\theta_1 + \cot^2\theta_2$$

D

$$\tan^2 \theta = \tan^2\theta_1 + \tan^2\theta_2$$