Which of the following fragments might cause errors?()
- A String s = "Gone with the wind";String t = " good ";String k = s + t;
- B String s = "Gone with the wind";String t;t = s[3] + "one";
- C String s = "Gone with the wind";String standard = s.toUpperCase();
- D String s = "home directory";String t = s - "directory";