Which two of statements are true？（）

A. It is possible to synchronize static methods.
B. When a thread has yielded as a result of yield（）， it releases its locks.
C. When a thread is sleeping as a result of sleep（）， it releases its locks.
D. The Object.wait（） method can be invoked only from a synchronized context.
E. The Thread.sleep（） method can be invoked only from a synchronized context.
F. When the thread scheduler receives a notify（） request， and notifies a thread， that thread immediately releases its lock.