The distance between two cities A and B is 330 km. A train starts from A at 8 a.m. and travels towards B at 60 km/hr. Another train starts from B at 9 a.m. and travels towards A at 75 km/hr. At what time do they meet?
A10 a.m.
B11 a.m.
C10 : 30 a.m.
D11 : 30 a.m.