9. Two 0.60 -kilogram objects are connected by a thread that passes over a light, frictionless pulley, as shown above. The objects are initially held at rest. If a third object with a mass of 0.30 kilogram is added on top of one of the 0.60 -kilogram objects as shown and the objects are released, the magnitude of the acceleration of the 0.30-kilogram object is most nearly
(A) 10.0m/s2
(B) 6.0m/s2
(C) 3.0m/s2
(D) 2.0m/s2
(E) 1.0m/s2