None.

(1) and (2) are both valid constructors for Thread.

(3), (4), and (5) are not legal Thread constructors, although (4) is close. If you reverse the 

arguments in (4), you'd have a valid constructor.

Option B is Correct. The start() method causes this thread to begin execution; the Java 

Virtual Machine calls the run method of this thread.

Option A is wrong. There is no init() method in the Thread class.

Option C is wrong. The run() method of a thread is like the main() method to an application. 

Starting the thread causes the object's run method to be called in that separately executing

 thread.

Option D is wrong. The resume() method is deprecated. It resumes a suspended thread.

By calling sleep() within main(), with long enough delay to ensure that all child threads 

terminate prior to the main thread.

None

To implement Runnable interface, a class needs only to implement a single method 

called run().