Which technical review is required for a successful Milestone B prior to the Engineering and Manufacturing Development Phase and occurs when all

Which technical review is required for a successful Milestone B prior to the Engineering and Manufacturing Development Phase and occurs when all major design issues have been resolved in the system preliminary design and work can begin on detailed design?

   Critical Design Review (CDR)

   Test Readiness Review (TRR)

   System Requirements Review (SRR)

   Preliminary Design Review (PDR)