5 4. a) Construct a B-tree for the following set of key values: (3, 4, 5, 7, 9, 14, 15, 21, 22 and 23) Assume that the tree is initially empty and values are added in ascending order. Construct B-trees for the cases where the number of pointers that will fit in one node is 6. b) Suppose the hash function is h(x) = x mod 11 and each bucket can hold at = 5 most two records. Show the form of extendable hash structure after each of the following insertion: 1, 4, 5, 7, 8, 2 and 19