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

[EX Q]: Sentence1: Great. I was finally able to get you into the Autumn House staring Friday for 3 nights and 3 people. your booking reference is C5ARPTZ2 . Sentence2: Sorry about the confusion earlier. I was able to book your room at Leverton House for Friday, 3 nights for 3 people. The reference number is U5B3PHWC . Sentence3: It was my pleasure. Goodbye! Sentence4: Can you try 3 nights instead? Sentence5: Perfect. I would like to book it for 3 people for 4 nights starting on Friday. Sentence6: Awesome. Thank you for everything! Sentence7: I can help you with a taxi. Please tell me your departure and destination sites along with your time frame. Sentence8: Yes let's try a different hotel. Sentence9: How about Cambridge Contemporary Art, on 6 Trinity St? Entrance is free. Sentence10: The Leverton House is a guesthouse located on the east side of Cambridge. What information are looking for? Sentence11: Both of them are booked solid for the days you requested. Would you like a hotel in a moderate price? Sentence12: I'd like to visit a museum if possible. Sentence13: Can they accommodate 3 people for 4 nights? Also, what are their phone numbers? Sentence14: I'm sorry. I am unable to book your stay. Could you arrive on another day or stay for a shorter amount of time? Sentence15: I'm sorry, it doesn't look like the Leverton House will be able to accommodate you. How about Allenbell or Autumn House? They are in the same area and also inexpensive. Sentence16: Can you please check for 3 nights at the same hotel for 3 people and can I have the reference number? Sentence17: I'm sorry both of those hotels are booked solid. Would you consider slightly more expensive accommodations? Sentence18: Okay. I'll need a taxi too. Sentence19: I want to leave the hotel by 22:00 to go to the Museum you mentioned. Sentence20: I'm looking for places to go in the centre of town. Sentence21: I'm also going to need a taxi, please. Sentence22: Sure. But I still need to book a hotel. Is there anything else available? Sentence23: Do you have the phone number for Autumn House's front desk? Sentence24: There are many attractions in the centre of town. Could you be more specific about what you're looking for? Sentence25: I'm looking for information on the Leverton House hotel. Sentence26: Sure. It's 01223575122. Anything else? Sentence27: They don't have a room available for 3 nights either. Anything else you'd like me to try? Sentence28: A black skoda will pick up up at Leverton House at 22:00 and bring you to Cambridge Contemporary Art Museum. The contact number is 07697068185. Question: Who has spoken the sentence 15? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: I am planning a trip in Cambridge and need a place to stay with free parking. Sentence2: Excellent. Can I book that for 2 people for 2 nights starting on Tuesday Sentence3: I have many different options available. Let me ask, do you have a certain price range or area in mind? Sentence4: Thanks i will find you one.Thanks a lot Sentence5: I have no particular price range, but would like a guesthouse in the north part of town. Sentence6: That narrows it down to about 9 different options. Most offer both free parking wifi. If you would like my personal recommendation, I would say go with the Hamilton Lodge. Sentence7: Booking was successful. Reference number is : 152UJWIK . anything else today? Sentence8: Yes, I need to find a train on Tuesday from Cambridge to London Liverpool Street. Question: Who has spoken the sentence 4? (A) User (B) System
[EX A]: Answer: (A) User

[EX Q]: Sentence1: Yes, please. For 5 people at 14:00 on monday. Sentence2: The camboats are located in the east, how's that? Sentence3: I do not have information on the fee. Sentence4: Ok, thank you. I'm also looking for a restaurant called don pasquale pizzeria. Sentence5: Your booking was successful with reference number 1RF57JD7 . Oh, by the way, your table will be reserved for 15 minutes. Enjoy! Sentence6: Have a lovely stay in Cambridge! Sentence7: Thank you for the reference number. Goodbye! Sentence8: That might be good. What is the entrance fee? Sentence9: Don Pasquale is in the centre. Would you like me to make a reservation? Sentence10: I'm looking for some boats in the East, actually. Question: Who has spoken the sentence 7? (A) User (B) System
[EX A]:
Answer: (B) System