二分检索算法对数组下标0-19的元素进行划分子问题，中间元素下标为（ ）\n \n \n \n \n \n \n

\n \n \n \n A.\n 10\n

\n \n

\n \n \n \n B.\n 9\n

\n \n

\n \n \n \n C.\n 8\n