We are very proud that Langfang is one of _____ in China. [ ]

A. the liveliest city

B. the liveliest cities

C. liveliest city

D. liveliest cities

继续盘问期间，经县级以上人民政府公安机关批准，公安民警可以对违法犯罪嫌疑人使用约束性警械。