Which one of the following has not been mentioned as a ground under section 24 rendering a confession by an accused person irrelevant?

Section 24 of the Evidence Act lists only three grounds that render a confession irrelevant: inducement, promise, and threat. Deceit is NOT mentioned as a ground in Section 24. The section specifically states that a confession made to a police officer is irrelevant if it appears to have been caused by inducement, promise, or threat. Deceit, while potentially relevant to confession voluntariness under other sections, is not one of the express grounds mentioned in Section 24.