The police force in California have been working to take down a statewide ring of drug dealers for the past six months. In order to help them do their job, they have decided to seek out someone that engages in criminal activity with the ring who is willing to give them inside information. What would the police force call this individual?

A.
insider

B.
tattletale

C.
assistant

D.
confidential informant

D. confidential informant