The growth of switching has (135) a new generation of network management tools that help (136) cope with the challenges, (137) them to correlate device alarms in order to (138) pinpoint root causes, or to monitor service levels without depending on IP subnet schemes. These new tools have become essential to coping with the primary (139) effect of any treatment that significantly increases network flexibility: added complexity.

138（）

A.technicians 

B.workers 

C.salesmen 

D.professors

客户交易保证金不足，期货公司履行了通知义务而客户未及时追加保证金，客户要求保留持仓并经书面协商一致的，穿仓造成的损失，期货公司（）。

A．不承担责任

B．承担次要赔偿责任

C．承担主要赔偿责任

D．全部承担赔偿责任