複選題21. Consider the red-black trec in Fig.2 (A)In Fig.2, after top-down inserting the key 86, then the color of key 86 is red. (B) In Fig.2, after top-down inserting the key 9, then the parent of key 9 is key 13. (C) In Fig.2, after top-down deleting the key 87, then the color of key 85 is red. (D) In Fig.2, after top-down deleting the key 10, then the parent of key 13 is key 15. E) The 2-3-4 tree representation of Fig.2 has height 2.