What is true about threads?

a) Threads of one process do not have access to each other's data (memory).

b) If you wish to define a class that extends a class MyString and implements the logic of the method run() for a Thread, you may define the class to implement the interface Runnable and use it during Thread creation.

c) The method wait() is used to wait for another thread to exit.

d) In every Java application, at least one thread is running.