Project Time Management includes the processes required to manage timely completion of the project, these processes interact with each other. ______ is following the process-Estimate Activity Durations.

A．Estimate Activity Resources

B．Define Activities

C．Develop Schedule

D．Sequence Activities

某债券票面金额F=100元，票面收益C=8元，每年支付一次利息，2年后还本。
根据以上材料，回答下列问题：

如某日该债券的市场价格为80元，则当期收益率为( )。

A．4%

B．5%

C．8%

D．10%