I am a movie director and I just received the following movie plot. Could you help me answer this question? If not, let me know by writing "Not answerable". Plot title: La ragazza che sapeva troppo Movie plot: On vacation, Nora Davis (Leticia Roman) arrives by plane in Rome to visit her elderly ailing aunt. Nora's aunt is being treated by Dr. Marcello Bassi (John Saxon). Nora's aunt passes away on the first night of Nora's visit and she walks to the nearby hospital to notify Dr. Bassi. On the way, she is mugged and knocked out in Piazza di Spagna. When she wakes up, she sees the body of dead woman, lying on the ground near her; a bearded man pulls a knife out of the woman's back. Nora reports this to the police in the hospital, who don't believe her when they find no evidence and think she's hallucinating. Later, at a cemetery, Nora meets a close friend of her aunt's, Laura Torrani (Valentina Cortese), who lives in the Piazza di Spagna. Laura plans to vacation soon and allows Nora to stay in her house for the remaining time of the vacation. Nora later explores Laura's closet and drawers and comes across newspaper clippings of articles on a serial killer dubbed the "Alphabet Killer" due to his having alphabetically killed people according to their surnames. The killer has already murdered victims whose last names begin with "A," "B," and "C," respectively. Nora also finds that the last victim Laura's sister, whom Nora had seen in a vision. According to the reports in the paper, this murder took place ten years ago. Nora then receives a telephone call, in which an anonymous voice tells her that "'D' is for death," and informs her that she will be the killer's next victim. Nora receives help from Dr. Marcello, who takes her on a trip to various Roman tourist sites to calm her down as they become more romantically interested in each other. When they return to the Craven house, she receives a call from a person who orders her to go to a particular address. Nora goes there, and she is guided to a vacant room. With Dr. Marcello, she discovers that the voice that guided her to this spot is tape recorded, and the voice warns Nora to leave Rome before it is too late. Nora and Marcello discover that the room is leased to... My question: What does the anonymous caller say to Nora during a phone call?
That "D" is for death