How frequently should Agile Release Trains release?

How frequently should Agile Release Trains release?
A . One per PI
B. On demand
C. Continuously
D. Once per iteration

Answer: B

Explanation:

Develop on Cadence, Release on Demand C ARTs apply cadence and synchronization to help manage the inherent variability of research and development. However, releasing is typically decoupled from the development cadence. ARTs can release a solution, or elements of a solution, at any time, subject to governance and release criteria.