I ______ her, but I never could.

A．ought to help

B．must help

C．ought to have helped

D．must have helped

网管及支撑系统专业管理类指标包括网管及支撑系统（）完整性，采集数据的完整性、准确性和及时性，网管及支撑系统可用性，网元接入网管及支撑系统的及时率。