A straight high way leads to the foot of a tower. Anil standing at the top of the tower observes a car at an angle of depression 30°. Six seconds later, the angle of depression of the car is found to be $$60^{\circ}$$. If the car is approaching the foot of tower with a uniform speed, the time taken by the car to reach the foot of that tower from this, the later point (in seconds) is

A

2

B

3

C

$$3\frac{1}{2}$$

D

4