7. Which of the following statements about time complexity is correct?
(A) When analyzing the time complexity of an algorithm, we count the number of executions of its keysteps. Using different key steps may lead to different results.
(B) In time complexity analysis, the best case is always smaller than the worst case.
(C) If Algorithm A has a higher time complexity than Algorithm B, then Algorithm A will always takemore time than Algorithm B for any input.
(D) The Big-O notation describes the best-case time complexity of an algorithm.