If ABCD is a rhombus and $$\angle ABC=60^\circ$$ then

A

The points A, B, C, D are concyclic

B

The quadrilateral has exactly half the area of the square with same sides as ABCD

C

The quadrilateral has area $$\frac{\sqrt{3}}{2}AB^2$$

D

The diagonals of the quadrilateral ABCD are equal and bisect each other at right angle