问题：

[单选]

1. import java.util.*； 
2. public class TestSet { 
3. enum Example { ONE， TWO， THREE } 
4. public static void main（String[] args） { 
5. Collection coll = new ArrayList（）； 
6. coll.add（Example.THREE）； 
7. coll.add（Example.THREE）； 
8. coll.add（Example.THREE）； 
9. coll.add（Example.TWO）； 
10. coll.add（Example.TWO）； 
11. coll.add（Example.ONE）； 
12. Set set = new HashSet（coll）； 
13. } 
14. } 
Which statement is true about the set variable on line 12？（） 

A .  The set variable contains all six elements from the coll collection， and the order is guaranteed to be preserved.
B .  The set variable contains only three elements from the coll collection， and the order is guaranteed to be preserved.
C .  The set variable contains all six elements from the coil collection， but the order is NOT guaranteed to be preserved.
D .  The set variable contains only three elements from the coil collection， but the order is NOT guaranteed to be preserved.