According to the Textbook,for the Law Enforcement Witness,what Is the First

According to the textbook,for the law enforcement witness,what is the first step in preparation for testifying in court?

A) Ensure that a complete investigation was conducted.
B) Ensure that all investigative leads were followed and all avenues explored.
C) Review all notes, reports, electronic recordings, and physical evidence prior to testifying.
D) All of the preceding are correct.