Consider a B+-tree in which the maximum number of keys in a node is 5. What is the minimum number of keys in any non-root node?
(A) 1
(B) 2
(C) 3
(D) 4
Answer: (B)
Explanation:

This solution is contributed by Anil Saikrishna Devarasetty
Another one:
Since the maximum number of keys is 5, maximum number of children a node can have is 6. By definition of B Tree, minimum children that a node can have would be 6/2 = 3. Therefore, minimum number of keys that a node can have becomes 2 (3-1).
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