The process of(72)schedule activity durations uses information on schedule activ

The process of(72)schedule activity durations uses information on schedule activity scope of work，required resource types，estimated resource quantities，and resource calendars with resource availabilities．

A．estimating

B．defining

C．planning

D．sequencing

A解析：估算活动历时的过程会用到活动工作范围、所需资源类型、估计的资源数量以及建立在资源可用性上的资源日历等信息。