Answer:
A. Ending
Step-by-step explanation:
In the given context, the word "expiration" means "ending" (option A). The sentence states that four years have passed, and now, at the end of those four years, not much new information or developments can be presented. "Expiration" here refers to the conclusion or termination of a specific period of time, indicating that the time period mentioned has come to an end. This understanding aligns with the sentence's mention of public declarations constantly being called forth during that time period. Therefore, option A, "ending," is the correct meaning of the word "expiration" in this context.