單項選擇題 1. public class A {
2.
3. private int counter = 0;
4.
5. public static int getInstanceCount() {
6. return counter;
7. }
8.
9. public A() {
10. counter++;
11. }
12.
13. }
Given this code from Class B:
25.A a1 =new A();
26. A a2 =new A();
27. A a3 =new A();
28. System.out.printIn(A.getInstanceCount() );
What is the result?()