![](https://cos-cdn.shuashuati.com/pipixue-wap/2020-1230-1107-56/ti_inject-812ce.png)
Given: Which code fragment, inserted at line 24, outputs "123abc 123abc"?()
A.
sb1.append("abc"); s1.append("abc");
B.
sb1.append("abc"); s1.concat("abc");
C.
sb1.concat("abc"); s1.append("abc");
D.
sb1.concat("abc"); s1.concat("abc");
E.
sb1.append("abc"); s1 = s1.concat("abc");
F.
sb1.concat("abc"); s1 = s1.concat("abc");
G.
sb1.append("abc"); s1 = s1 + s1.concat("abc");
H.
sb1.concat("abc"); s1 = s1 + s1.concat("abc");