单选题：Given S = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 } and 9 equivalen

Given S = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 } and 9 equivalence relations: 3\~4，6\~8，9\~11，2\~3，1\~11，3\~11，5\~8，1\~7，11\~4. After invoking successively these relations with union-by-size（if the two sizes are equal, the smaller element will be the root）and path compression, which one of the following statements is false?
@[D](3)

A. there are 3 equivalence classes
B. the parent of element 1 is element 3
C. all elements are either a root or a child of a root
D. the parent of element 11 is element 9



A.there are 3 equivalence classes
B.the parent of element 1 is element 3
C.all elements are either a root or a child of a root
D.the parent of element 11 is element 9


答案：D