You are designing a network, which needs to support 55 users. You don't plan to extend the segment beyond the current number of users. Which subnet mask would best meet your needs?
A. 255.255.0.0
B. 255.255.255.0
C. 255.255.255.192
D. 255.255.255.160
题目要求:不在现有用户数上拓展分段,如何设定subnet mask,是吗,那么答案是b?c和d都增加了新的子网,所以不选,是吗