An author is planning a narrative about a jewelry thief. Which of the following is the best choice for an unreliable narrator?

An eyewitness to each of the crimes who is providing their story to police as evidence
An omniscient narrator who gives the truthful perspective of each character in the story
The detective who catches the thief, using first person narration to reveal what happens in real time
The jewelry thief explaining their side of the story and what led to their life of crime