Extreme Programming (XP) is a discipline of software development with (71) of simplicity, communication, feedback and courage. Successful software development is a team effort - 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 and helps them to succeed together. XP is aimed primarily at object-oriented projects using teams of a dozen or fewer programmers in one location. The principles of XP apply to any (72) project that needs to deliver quality software rapidly and flexibly.
An XP project needs a (73) customer to provide guidance. Customers, programmers, managers, are all working (74) to build the system that’s needeD．Customers - those who have software that needs to be developed - will learn simple, effective ways to (75) what they need, to be sure that they are getting what they need, and to steer the project to success.
（73）处应填（）。
A．part-time
B．casual
C．seldom
D．full-time