What does Milestone B signify in a program's lifecycle?

Milestone B is a critical point in a program's lifecycle, marking the transition from the concept development phase into the actual development of a system. This milestone signifies that the program has matured to the extent that it can transition to a program of record, meaning that it has received the necessary approvals to move forward. At this stage, the program is authorized to enter into the engineering and manufacturing development phase, where the design and development of the system will be further defined and an acquisition strategy will be established.

Choosing this answer reflects an understanding of the structured progression in defense acquisition processes, where Milestone B serves as a gateway for projects that are moving from conceptual planning into executable development phases.