ExtremeProgramming（XP）isadisciplineofsoftwaredevelopmentwith①（）ofsimplicity，communication，feedbackandcourage．Successfulsoftwaredevelopmentisateameffort-notjustthedevelopmentteam，butthelargerteamconsistingofcustomer，managementanddevelopers．XPisasimpleprocessthatbringsthesepeopletogetherandhelpsthemtosucceedtogether．XPisaimedprimarilyatobject-orientedprojectsusingteamsofadozenorfewerprogrammersinonelocation．TheprinciplesofXPapplytoany②（）projectthatneedstodeliverqualitysoftwarerapidlyandflexibly．AnXPprojectneedsa③（）customertoprovideguidance．Customers，programmers，managers，areallworking④（）tobuildthesystemthat’sneeded．Customers-thosewhohavesoftwarethatneedstobedeveloped-willlearnsimple，effectiveWaysto⑤（）whattheyneed，tobesurethattheyaregettingwhattheyneed，andtosteertheprojecttosuccess．

①（）

A.importance

B.keys

C.roles

D.values