Multiple choice:In a tree T with degree 4, if there are 20 nodes with degree 4, 10 nodes with degree 3, 1 node with degree 2 and 10 nodes with degree 1, then the number of leaf nodes of tree T is zero（
In a tree T with degree 4, if there are 20 nodes with degree 4, 10 nodes with degree 3, 1 node with degree 2 and 10 nodes with degree 1, then the number of leaf nodes of tree T is ().
A.41
B.82
C.113
D.122
answer：B
A.41
B.82
C.113
D.122
answer：B
