第26656题 单选
下列二分枚举算法的代码框架中,{ }处应填入的程序是()

下列二分枚举算法中,{ }处应该填入的程序是({}不算作程序的一部分):

def binary_search(arr, x):
    low = 0
    high = len(arr) - 1
    while low <= high:
        { }
    return -1
A
mid = (low + high) // 2
if arr[mid] == x:
    return mid
elif arr[mid+1] > x:
    high = mid - 1
else:
    low = mid + 1
B
mid = (low + high) // 2
if arr[mid] != x:
    return mid
elif arr[mid+1] > x:
    high = mid - 1
else:
    low = mid + 1
C
mid = (low + high) // 2
if arr[mid] == x:
    return mid
elif arr[mid] > x:
    high = mid - 1
else:
    low = mid + 1
D
mid = (low + high) // 2
if arr[mid] != x:
    return mid
elif arr[mid] > x:
    high = mid - 1
else:
    low = mid + 1