A project manager is leading a state-of-the art billing system project. The project manager has checked the existing billing system, as well as the lessons learned repository in the company’s project management information system (PMIS). The project manager would like to gather more system requirements.What should the project manager do next? 项目经理正在管理一个先进的计费系统项目。项目经理已经检查了现在的计费系统以及公司项目管理信息系统（PMIS）中的经验教训知识库。项目经理将可能收集更多的系统需求。项目经理下一步应该怎么做？ ◑A.Refer to existing industry best practices.参考所有的行业最佳实践。 ◑B.Consult any experienced internal or external group.咨询任何有经验的内部或外部团队。 ◑C.Work with external subject matter experts (SMEs).与外部主题专家（SME）一起工作。 ◑D.Work with internal business and technical support resources.与内部业务和技术支持资源一起工作
