During the development of MEBTO, which phase occurred in September 2013?

• A. Pilot program
• B. Field trial
• C. Final rollout
• D. Proof of concept phase

Answer: (D)

In development, establishing that the idea can work in principle happens during the proof of concept phase. This stage focuses on validating the essential assumptions with a small, focused effort to show feasibility and potential value before committing to broader testing or deployment. That makes September 2013 a plausible time for this milestone, since it marks a point where the concept is demonstrated to be workable enough to justify moving on to more extensive testing.

The other stages involve progressively larger-scale testing or deployment: a pilot program tests a more complete version in a real but controlled environment; field trials push the system into real-world use with more users and scenarios; and a final rollout is the full deployment across the intended environment. So the milestone in September 2013 best aligns with the proof of concept phase.