In which of these phases is a detailed design of a proposed customer solution developed？（）

A.Plan
B.design
C.prepare
D.operate

A.Staging
B.Business Requirements Development
C.Post Implementation Support Handoff Meeting
D.Detailed Design Development
E.Staff Training
F.Incident Management

A.initiation planning analysis design development implementation operations and maintenance
B.project planning， site assessment risk assessment solution selection and acquisition， testing， and operations
C.prepare， plan， design， implement operate， and optimize
D.analysis， design， deployment testing， implementation， and production
E.presales， project planning， development implementation， operations testing， and operations sign- off