6. (10\%) We have an B-tree of order 3 in the following. Please fill in the blanks for performing corresponding operations. Notice that these operations are performed of A, B, C, D and E, independently. To formulate your answer, key 8 's two children nodes are shown in the form of ([2.4], [15]), for example. (A) delete 3 children nodes for the node containing key 8 : (B) insert 35 children nodes for the node containing key 35 : (C) delete 30 children nodes for the node containing key 15 : (D) delete 4 children nodes for the node containing key 5 : (E) insert 7 children nodes for the node containing key 6