施工企业在工程投标阶段编制的估算成本计划是一种( )成本计划。

A．作业性
B．实施性
C．竞争性
D．指导性

Thirty-five percent of the breaking strength of an anchor cable is generally accepted as the（）.

A.safe operating load

B.normal operating tension

C.emergency working load

D.allowable storm load