计算题

DRAG DROP Click the Task button.

问答题DRAG DROP Click the Task button.

问答题DRAG DROP Click the Task button.

问答题DRAG DROP Click the Task button.

问答题DRAG DROP Click the Task button.

单项选择题Given: Which code, inserted at line 4, guarantees that this program will output [1, 2]（）?

A.Set set = new TreeSet();
B.Set set = new HashSet();
C.Set set = new SortedSet();
D.List set = new SortedList();
E.Set set = new LinkedHashSet();