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

会员在期货交易中违约的，期货交易所先以该会员的保证金承担违约责任。（）