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 coll collection， but the order is NOT guaranteed to be preserved.
D.The set variable contains only three elements from the coll collection， but the order is NOT guaranteed to be preserved.

A.insert a call to this（） in the Car constructor
B.insert a call to this（） in the MeGo constructor
C.insert a call to super（） in the MeGo constructor
D.insert a call to super（vin） in the MeGo constructor
E.change the wheelCount variable in Car to protected