How long has it been since Robin last visited his birthplace?

The correct answer indicates that it has been more than twenty years since Robin last visited his birthplace. This implies that Robin's absence from his birthplace extends beyond the threshold of two decades. Such phrasing suggests a significant passage of time, which conveys a deeper contextual understanding of how much life can change over such a long duration.

The emphasis on "more than twenty years" also suggests that Robin's experiences and identity may have evolved considerably during this time. This can hint at potential themes of nostalgia or the impact of time on personal history and relationships, allowing for richer interpretations of Robin's connection to his birthplace.

The other options provide narrow time frames that do not align with the idea that Robin has been away for a longer duration, thus contrasting with the significance of the chosen response.