一个小区最多可有（）个用于上行同步建立的上行导频信道UpPCH同时存在。

A.4

B.8

C.16

D.32

--- How soon will you start your journey?

--- I'm not sure.  I haven't decided_______.

A．when shall I ask the boss for leave

B．where I will go to spend the holiday

C．if I would go by train or by plane

D．who should I travel with