In your project, you realize the importance of determining the start and finish dates for project activities. If the project start or end dates are not realistic, then the project may not be completed on time. This is done as part of ______ .

A．activity sequencing

B．activity duration estimating

C．schedule development

D．activity definition

下列IP地址可以作为组播地址的有（）。

A、202.120.11.1

B、224.0.11.255

C、239.255.255.255

D、252.102.1.1