Six years ago, a Miami woman walking through the hall of an office building casually noticed two men standing together. Several minutes after her leaving, the men murdered a person working in the building. Police investigators determined that the woman was the only witness who had seen the two suspects, and could possibly describe them. In an interview with police, her memory of the men proved disappointingly unclear.Several days later, psychologist Ronald P. Fisher was brought in to obtain a more complete account from the woman. Fisher"s interview produced abreakthrough(突破)—the woman reported a clear picture of one of the suspects. She then recalled several details about his appearances. This information gave police important leads that enabled them to arrest the suspects and close the case.Police investigators sought the help from Fisher because of his rich knowledge in conducting the so-calledcognitive(认知的) interview, a kind of memory-rebuilding process. In its original form, the cognitive interview focuses on guiding witnesses through four general recalling techniques: thinking about physical surroundings and personal feelings that existed at the time of past events, reporting everything that comes to mind about those events no matter how broken or unconnected, retelling events in a variety of time orders, beginning to end, end to beginning, forward or backward, and adopting different perspectives while recalling events.Usually, an interviewer begins the cognitive approach by encouraging the witness to take an active role in recalling information rather than giving answers only to someone else"s questions. The witness first describes what happened in his or her own words, with no interviewer interruptions. The interviewer then goes further with specific techniques, such as having the witness tell the details of what happened from different perspectives.Experiments with police detectives trained in this demanding interview method find that they get nearly 50% more information from witnesses than before training, while error rates remain about the same. It can be inferred from the passage that in a cognitive interview, the interviewer mainly plays a ______ role.

A. directing
B. questioning
C. passive
D. secondary