To understand the output of the given code, the user needs to know about the order of initialization of static and non-static blocks, constructors, and the concept of inheritance.
When the main method is executed, the following sequence of events will occur:
The static block of class B will be executed first. It will print "r1 r4".
The static block of class C will not be executed because it is not defined.
The print statement inside the main method will execute and print "pre".
A new object of class C is created using the default constructor.
Since class C extends class B, the constructor of class B will be called first.
Before the constructor of class B is called, the non-static block of class A will be executed. It will print "b1".
The constructor of class B will be executed next. It will print "b2" and "r2".
Before the constructor of class C is called, the non-static block of class B will be executed. It will print "r3".
The constructor of class C will be executed last. It will not print anything.
After the constructor of class C is called, the print statement inside the main method will execute and print "post".
Therefore, the output will be:
The Answer is: A) r1 r4 pre b1 b2 r3 r2 post