A.10 B.9 C.7 D.8
A.212,214,216,218 B.216,214,212,218 C.214,212,218,216 D.218,216,212,214
A.head=head→next;p=NULL B.head=head→next;p→next=head C.head→next=p→next D.head=head→next;p→next=NULL