Final answer:
An event is a relation among individual entities and values that can change over time. The correct completion for the sentence is 'dynamic and evolving over time'.
Step-by-step explanation:
An event is a relation among individual entities and values, which can change over time. In this context, the correct completion for the sentence is d. dynamic and evolving over time. Events are not static; they can change and have an impact on the entities involved. For example, in history, events like wars and revolutions are dynamic and evolve over time, causing significant changes.