The base of a cliff is circular. From the extremities of a diameter of the base, angles of elevation of the top of the cliff are 30o and 60o. If the height of the clif is 500 m, then the diameter of the base of the cliff is
(a) 2000/√3 m
(b) 1000/√3 m
(c) 2000/√2 m
(d) 1000√3 m
