Just because a chunk of code is not executed does not mean it is not compiled. All of the code is compiled - both constructors. As each constructor contains a local class, a class file is generated for each local class. If you compile this code, you'll find that the following class files are generated:
A.class
A$1B.class
A$2b.class
C.class
Therefore, option 4 is correct.
However, this will not appear on the
SCJP exam.