Extreme Programming（XP）is a discipline of software development with___1___of simplicity,communication,feedback and courage.Successful software development is a teameffort-not just the development team,but the larger team consisting of customer,management and developers.XP is a simple process that brings these people together andhelps them to succeed together.XP is aimed primarily at object-oriented projects using teamsof a dozen or fewer programmers in one location.The principles of XP apply to any__2____project that needs to deliver quality software rapidly and flexibly.An XP project needs a（an）___3__customer to provide guidance.Customers,programmers,managers,are all working___4__to build the system that'sneedeD．Customers-those who have software that needs to be developed-will learn simple,effective ways to___5___what they need,to be sure that they are getting what they need,and to steer the project to success.
1、____
A.importance
B.keys
C.roles
D.values