泳池开放期部门负责人现场巡查的频次是（）。

______ attractions you are planning to visit in that island country, you'd better book your hotel _____

because the hotels are always full in the tourist seasons. [ ]

A. Whatever; in the advance                

B. Wherever; before hand  

C. Whichever; in advance                  

D. Whosever; before hand