When is precedent not followed?

a. when circumstances have changed

b. when technology has changed

c. when there are changes in the factual circumstances from those in which the precedent was established

d. it is possible that precedent would not be followed in all of the above circumstances?

Precedent, in the given question, refers to a legal case that establishes how cases of a similar nature in the future should be handled based on the results from the judicial court. Generally, precedent is followed in most cases, even when the technology has changed, or circumstances are different from the precedent - as long as the underlying principles are the same.

In this case, the best answer to the question would be (C) when there are changes in the factual circumstances from those in which the precedent was established, the precedent can no longer be used since it means that the two cases now have different underlying principles.