Subject is Enterprise Architecture

Which of the following are reasons to decide to use a transient artifact rather than a persistent artifact?

a. Simple, easily understood artifacts such as User Does/System Does matrix are very helpful as transient artifacts that can jumpstart the design.

b. If an artifact is helpful to drive to a decision, but will result in a tradeoff of more overhead for less long-term value, a transient artifact will be a good choice.

c. Transient artifacts are wasteful at the most detailed design levels. It is usually better to use the database schema, the class structure, the code or other long-lived machine-readable artifacts at the detailed levels.

d. Transient artifacts should be preserved in case someone later needs to understand the system.