Which of the following are the functions of project quality assurance? （ ）

A、Itattemptstoensuretheprojectisclosetotherequiredqualitylevel.
B、Itshouldbeperformedthroughouttheproject.
C、Itcanprovideconfidencethattheprojectwillmeetmostoftherequiredqualitystandards.
D、Itistheareawheretheprojectmanagercanhavethegreatestimpactontheprojectquality.