Ina circle with centre O, AD is a diameter and ACis a chord. B is a point on AC, such that OB = 5 cm and $$\angle$$OBA = $$60^\circ$$ If $$\angle$$DOC = $$60^\circ$$, then what is the length of BC ?

A

$$5\sqrt3$$ cm

B

5 cm

C

$$3\sqrt5$$ cm

D

4 cm