From the top of a building, the angles of elevation and depression of top and bottom of a tower are $$60^\circ$$ and $$30^\circ$$respectively. If the height of the building is 5 m,then the height of the tower is:

A

$$20  m$$

B

$$15  m$$

C

$$10\sqrt{3}  m$$

D

$$5\sqrt{3}  m$$