These are all "arrangements" of the same piece. The original movie release was scored for orchestra (also likely by someone other than the original writers), so in that sense, none of them is correct. Each one, however, is arranged for different levels of pianist. The first is intended for an intermediate level player, while the other two are intended for late and early beginning pianists.
This is the norm for popular songs like these. They often exist in many different versions to appeal to different levels of play — as the above — or different styles of play, such as jazz or a duet with a singer.
In these situations, however, it is always necessary to credit the original composer(s)/lyricist(s) — sometimes by law, sometimes by contractual agreement, and sometimes by professional ethics.