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

Options

A. 4 cm
B. `3sqrt(5)` cm
C. `5 sqrt(3) cm`
D. 5 cm

Answer

D