在下列有关Windows 98/XP文件管理功能的叙述中，正确的是

A．文件名中可使用一切可打印字符

B．系统以簇(CIuster)为单位分配磁盘空间，簇的大小与磁盘分区大小及其采用的文件系统类型等有关

C．对于同一个硬盘来说，在利用分区操作将其分为多个分区时，所有分区必须采用同一种文件系统

D．磁盘根目录中可存储文件的个数，仅与磁盘可用存储空间大小和文件大小相关，与此采用的文件系统无关

One of the most widely used routing protocols in IP networks is the Routing Information Protocol (RIP)．RIP is the canonical example of a routing protocol built on the (71) algorithm．Routing protocols in internet works differ slightly from the idealized graph model．In an internet work，the goal of the routers to forward (72) to various networks．
Routers running RIP send their advertisement about cost every (73) seconds．A router also sends an update message whenever an update from another router causes it to change its routing table．
Routing protocols use different techniques for assigning (74) to individual networks．Further, each routing protocol forms a metric aggregation in a different way．RIP takes the simplest approach，with all link costs being equal (75) ．Thus it always tries to find the minimum hop route．Valid distances are 1 through 15．This also limits RIP to runing on fairly small networks．

A．data frames
B．segments
C．packets
D．messages