Q. 21 Breadth First Search (BFS) is started on a binary tree beginning from the root vertex. There is a vertex t at a distance four from the root. If t is the n-th vertex in this BFS traversal, then the maximum possible value of n is ________
(A) 15
(B) 16
(C) 31
(D) 32
Answer: (C)
Explanation:
