How many years ago was the Silver Anniversary Convention held from now?

The Silver Anniversary Convention refers to a celebration marking 25 years since the establishment of an organization or significant event. Therefore, if the convention took place 25 years ago, it directly correlates to the standard definition of a "silver anniversary." In this context, celebrating 25 years is significant in various traditions, highlighting its importance in recognizing milestones.

The other choices suggest longer timeframes, which do not fit the definition of a "silver anniversary." This term specifically indicates a quarter of a century, making the correct answer a reflection of the foundational anniversary timeframe. Understanding these milestones helps reinforce the significance of the Silver Anniversary Convention within the organization’s history.