William is the detective investigating a missing person case.
Which of the sources is a secondary source?
A. Mother of missing person interview (on record - Police Station on February 13) - Mother claims she received a call from a payphone; caller hung up immediately.
B. Possible missing person security video outside payphone on February 13 - Person matching the missing person description picked up the payphone, dialed, and hung up.
C. Restaurant worker interview (on record at deli beside payphone on February 13) - Heard a man and woman arguing who math the missing person and suspect descriptions.
D. Tele Service phone records of the missing person's home on February 13 - Phone record shows one second incoming call from payphone.
