Which of the Following Is a Violation of the Miranda

Which of the following is a violation of the Miranda ruling?

A) ​tape-recording unknowing suspects who were placed alone in a patrol car under arrest
B) ​using a jail informant to report what a suspect tells him or her
C) ​placing a tape recorder in an interrogation room while leaving the suspect alone
D) ​directly questioning the suspect about the crime while in a patrol car and en route to the jail