In the below code, which code fragment should be inserted at line 3 so that the output will be: “123abc 123abc”? 1 StringBuilder sb1 = new StringBuilder("123"); 2 String s1 = "123"; 3 // insert code here 4 System.out.println(sb1 + " " + s1);

• A. sb1.append(“abc”); s1.append(“abc”);
• B. sb1.append(“abc”); s1.concat(“abc”);
• C. sb1.concat(“abc”); s1.append(“abc”);
• D. sb1.append(“abc”); s1 = s1.concat(“abc”);