多选题 Given:
2. public class Maize {
3. public static void main(String[] args) {
4. String s = "12";
5. s.concat ("ab");
6. s = go(s);
7. System.out.println(s);
8. }
9. static String go(String s)
10. s.concat("56");
11. return s;
12. } }
What is the result?