Choice of Damnations

• WWizards of the Coast2005-06-01
  Official Ruling
  After the opponent chooses a number, Choice of Damnations’ controller may choose to make that opponent either lose that much life or make that opponent sacrifice permanents.
• WWizards of the Coast2005-06-01
  Official Ruling
  If the opponent must sacrifice all but a number of permanents, that opponent chooses that many permanents and then sacrifices the rest. If the number chosen is greater than the number of permanents the opponent controls, the player sacrifices nothing.

Rulings via Scryfall