Determine output:class A{{System.out.print("b1 ");}public A(){System.out.print("b2 ");}}class B extends A{static{System.out.print("r1 ");}public B(){System.out.print("r2 ");}{System.out.print("r3 ");}static{System.out.print("r4 ");}}public class Test extends B{public static void main(String[] args){System.out.print("pre ");new Test();System.out.println("post ");}}