A
5 is the correct answer. To find maximum no of nodes newly created, assume that all nodes are full. Adding one more to leaf will split the leaf at level 4 (+1) , the middle element moves up and splits the parent node at level 3 (+2), similiarly a split at level 2(+3) , and now at root node a split (+4) and its middle element forms a new root node(+5). Now the B tree has 5 Levels with 5 new nodes created