State whether each of the following is true or false. If false, explain why.

a) Method sleep does not consume processor time while a thread sleeps.

b) JavaFX components are thread safe.

c) Declaring a method synchronized guarantees that deadlock cannot occur.

d) Once a ReentrantLock has been obtained by a thread, the ReentrantLock object will not allow another thread to obtain the lock until the first thread releases it.