题目7单选题
程序段 FOR i:=n-1 DOWNTO 1 DO FOR j:=1 TO i DO IF A[j]>A[j+1] THEN A[j]与A[j+1]对换;其中 n为正整数,则最后一行的语句频度在最坏情况下是( )A. O(n)B. <img src="https://tihai-oss-cloud.itihey.com/img/14e925378ae4c3ddad8fdf29aceb4a92.webp">C. <img src="https://tihai-oss-cloud.itihey.com/img/6538d45dbd08a9fcdc42d77bef1f00c2.webp">D. <img src="https://tihai-oss-cloud.itihey.com/img/67f953332c938e39f537fdf77e7e0ea1.webp">