34. HashMap props = new HashMap(); <br /> 35. props.put(”key45”, “some value”); <br /> 36. props.put(”key12”, “some other value”); <br /> 37. props.put(”key39”, “yet another value”); <br /> 38. Set s = props.keySet(); <br /> 39. // insert code here <br /> What, inserted at line 39, will sort the keys in the props HashMap?() 
A、 Arrays.sort(s);
B、 s = new TreeSet(s);
C、 Collections.sort(s);
D、 s = new SortedSet(s);