Objects eligible for garbage collection

Question

This question was taken from Kathy Sierra SCJP 1.6. How many objects are eligible for garbage collections?

According to Kathy Sierra\'s answer, it is C.

Answer 1

c3 is null, so there is clearly no Object there eligible for garbage collection.

Note that only two CardBoard objects are created, the two on these lines:

CardBoard c1 = new CardBoard();
CardBoard c2 = new CardBoard();

and after the reference juggling, only one of them is without references.