Dean Campenella is a detective with California state police. During the investigation of a missing child, Campenella found new clues that led to the capture of a serial killer involved in another case. Since Campenella was not involved in the serial killer case, and found the clues while investigating another case, Campenella demanded a special reward from the state police department for helping catch the killer. But his demand was declined citing lack of consideration. Campenella's demand lacks consideration under which of the following?

gift promise

preexisting duty

illegal consideration

illusory promise