Enthuware

How is A correct? I thought Runnable was an interface and could therefore not be instantiated? What are you passing to 'Thread t' if 'Runnable a' isn't instantiated?

You are right. An interface cannot be instantiated. But here in option A, when you do new Runnable(){ ... } you instantiate an anonymous class that implements Runnable interface.

HTH,
Paul.

Thanks, that makes sense.

Why the correct answers are not OnlyA and OnlyC because you cannot put them together the A and C portions of code, because they use same identifier a as a Thread or as a Runnable, so you can put only one piece of code once, A or C. Otherwise what sense makes the last two options?

That is because the question wants you to select two options. So if one thinks that option C is not right and A is right, he can select A and Only A.
select the options Only A and Only C, will not make sense.

Finally, the right anwer is A and C.

HTH,
Paul.