The earned value technique is a commonly used method of performance measurement．It integrates project scope，schedule，and cost measures to help the project management team assess project performance．If a project’s Cost Performance Index(CPI＝EV/AC)value less than 1．0，it means that（ ）。

A．the cost savings for work completed

B．the project is ahead of its planned schedule

C．the cost overrun for work completed

D．1ess work was completed than was planned