You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

[EX Q]: Sentence1: Okay, the TR8944 leaves at 15:39 and arrives by 17:07. Would you like me to book tickets for you? Sentence2: There are 10 trains leaving fro Liverpool Street on Thursday. Did you have a departure time in mind? Sentence3: Okay I have booked you and your reference number is WLUOQKEV . Sentence4: rosa's bed and breakfast is in the cheap price range Sentence5: I'm looking for a train departing from london liverpool street leaving on thursday. Sentence6: Do you need a taxi? Sentence7: Goodbye, and thanks again. Sentence8: Yes, I don't want to leave for Cambridge until 15:00 at the earliest. Sentence9: Sure thing. Thanks for letting us help you today! Sentence10: Thank you. I also need a hotel in the south. Sentence11: then thanks for inquiring with us. Sentence12: I don't need a taxi, thanks for asking Sentence13: No price range but I do want a 4 start. Sentence14: Yes, for 6 people. Sentence15: What price range are you interested in? Sentence16: That sounds great. I'll need a reservation for 6 people for 4 nights on Thursday. Sentence17: I've gone ahead and booked that for you. Your Reference number is : EUZ34KY9 . Is there anything else I can assist you with today? Sentence18: No, that takes care of everything I need. Thanks! Question: Who has spoken the sentence 7? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: We have nine expensive dining establishments on the west side. Cuisines offered are Thai, Indian, European, and British. Do you have a preference? Sentence2: Thank you. Can you please give me the reference number? Sentence3: The reference number is 5WHDPGHW .. Is there anything else I can assist you with? Sentence4: Okay I booked a table for 4 at 15:00 on Saturday at the Graffiti, an expensive British restaurant in the west area of town. Sentence5: I am interested at eating at an expensive place in the west part of town. Sentence6: No that will be all. Thank you so much for all of your help! Sentence7: Excellent. Have a good rest of your day! Sentence8: No I don't have a preference. I want to book for four people at 15:00 on Saturday. Question: Who has spoken the sentence 5? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: There are 70 results. Is there a certain day or time you'd like to leave? Sentence2: May I have the postcode as well ? Sentence3: Find me a train out of Cambridge to london kings cross Sentence4: i also need a place to dine. Sentence5: Yes I have booked that for you and your reference number is E3M7QM9F . Sentence6: You're welcome. Have a nice day! Sentence7: TR1006 arrives at 19:51, would that work? Sentence8: Here you go cb30ad Sentence9: Yes, British food in the West would be great! Sentence10: Great, thanks very much, that's all I need! Sentence11: Saint johns chop house serves british food in the west. Sentence12: I need it on Friday and it should arrive at London Kings Cross by 21:45. Sentence13: I guess that will work. Can you please make a booking for 3 people and when you are through may i also have the booking reference number. Sentence14: 01223353110 is the number. Sentence15: Is there a particular cuisine or location that I can recommend for you? Sentence16: What is the phone number and postcode to Saint Johns Chop House? Question: Who has spoken the sentence 15? (A) User (B) System
[EX A]:
Answer: (B) System