When did our chapter last win a True Merit bowl?

The correct answer is based on the context that indicates last year was the most recent occasion the chapter won a True Merit bowl. This aligns with the notion that a "True Merit bowl" is awarded periodically, and by selecting last year, it reflects a recent achievement that is still fresh in the minds of the members of the chapter.

The other time frames, such as this year, two years ago, and three years ago, do not match the criteria of being the last win, as they suggest either a more recent win that hasn't occurred yet or wins that happened further back in time. Thus, last year is the most accurate answer, standing as the latest accomplishment for the chapter.