In the original DOOM (1993) which of the following is NOT a cheat code?

The answer is IDCLIP because it is not a cheat code in the original Doom (1993). IDCLIP is a command used to enable the "no-clipping" mode, which allows the player to move through walls and other objects. However, this command was only introduced in the later versions of Doom, not in the original release. The original Doom cheat codes included various options such as god mode (IDDQD), all weapons and keys (IDKFA), full health (IDFA), and more, but IDCLIP was not among them.