A general guideline in designing an efficient self-adjusting data structure is a. to add a simple and uniform self-adjusting feature to the operations that tends to improve the efficiency of the future operations. b. to ensure an operation does not increase the potential significantly c. to enforce as little "balance" constraint as possible. d. to maintain as little "balance" information as needed. The structure of an arbitrary binary tree is uniquely determined by the following two sequences of its nodes. If more than once choice is correct, select the red choice. a. The pre-order sequence and the level-order sequence b. The pre-order sequence and the in-order sequence. c. None of the other choices are correct. d. More than one of the other choices are correct. e. The pre-order sequence and the post-order sequence