请选出以下程序的输出结果class A {public void func1() {System.out.println("A func1 is calling");}public void func2() {func1();}}class B extends A {public void func1() {System.out.println("B func1 is calling");}public void func3() {System.out.println("B func3 is calling");}}class C {public static void main(String[] args) {A a = new B();a.func1();a.func2(); a.func3();}}