In "One Piece", which one of the following is NOT an Ancient Weapon?

In the manga and anime series One Piece, the ancient weapons are powerful and destructive tools with immense abilities. While the other options - Pluton, Uranus, and Poseidon - are all established ancient weapons within the series, Jupiter is not mentioned or recognized as one. Its absence is due to the fact that Jupiter does not hold any significance or mention in the One Piece story and lore. Therefore, Jupiter is the correct answer as the one that is not an ancient weapon in the One Piece series.