A 47- year- old police officer presents in an outpatient clinic for evaluation of "weird experience". He says he was out of my mind, really paranoid" for a full 2 weeks, but then completely recovered. His symptoms began shortly after one of his colleagues was inexplicably shot during a routine traffic stop. Although everyone in the department has been upset by the event, the pt found himself increasingly preoccupied with what he called "mysterious signs and circumstances" around the time of the tragedy and what he felt was the police chief's desire to "sweep it all under the carpet". Two days after the event, he began to hear voices on his car radio warning him about surveillance by "corrupt" members of the police department, who were "trying to bring him over" to their side with "brainwashing KGB techniques". Soon after, he began to hear a "whine" from his earpiece, which he recognized as the brainwashing. Unable to bear it any longer, he crushed the earpiece. Although he was able to pass this off an an accident at the time, he remains terrified that he might "lose it" agin. Subsequently, he returned to his usual state and did not experience further psychotic symptoms. What is the likely diagnosis?

A. Brief psychotic disorder.
B. Delusional disorder, persecutory type.
C. Schizophrenia.
D. Schizophreniform disorder.