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

[EX Q]: Sentence1: Thank you for your help. Sentence2: do you have one with a star of 4? Sentence3: You're welcome, and have a great day. Sentence4: yes please tyhat you for all your help Sentence5: OK, you have 7 tickets reserved on TR6939. Total due at the station will be 116.2GBP. Your reference number is OK7WYTNQ . Sentence6: Try either one of the cheap ones, I need one that can hold my group of 7 for 5 nights on tuesday. Sentence7: Yes, I'll need 7 tickets. Sentence8: I also need a place to stay. 2 star is my preference. Sentence9: I would like to arrive in Cambridge by 08:45. Sentence10: We have 10 different trains on that day. Do you prefer a particular time? Sentence11: No, thank you. That will be all. Sentence12: TR6939 is your best option. It will leave at 05:39 and arrive at 07:07. Would you like to book passage on that train? Sentence13: In the west part of town. The price doesn't matter. Sentence14: the cambridge belfry was the best match for a large group so I booked you there, the reference number is X33MYBK5 , may I assist with anything else? Sentence15: Have a great time. Sentence16: I do. We have three options. Two that are cheap and one that's expensive. Do you have a preference? Sentence17: I need help finding a train. Can you do that? Sentence18: I don't have any 2 star hotels in that area. Would you like a different area or a higher rated hotel? Sentence19: Okay, do you need a reference number? Sentence20: Of course. Where are you traveling to? Sentence21: I would like to leave Liverpool street on Tuesday and arrive in Cambridge. Sentence22: okay, what area and price range? Question: Who has spoken the sentence 15? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: Thank you. That's all I need. Sentence2: I was able to book it, reference number is T2SNWPJA Sentence3: Okay, the Mahal of Cambridge serves indian food and is located in the centre. Would you like me to make a reservation for you? Sentence4: I am happy to help, what was the name of the place? Sentence5: Its the huntingdon marriot. I'd like to book it for 8 people on 2 nights starting on wednesday, and I'll need a reference number. Sentence6: Can you help me look up a particular hotel that I have in mind? Sentence7: Great, thanks for that. I'm also looking for information about a restaurant called mahal of cambridge. Sentence8: Yes please book a table on Wednesday for 8 people at 17:15, I'll need a reference number. Sentence9: It was my pleasure to help. Have a wonderful night. Take care. Bye. Sentence10: Your booking was successful reference number is 1QVLVD25 Question: Who has spoken the sentence 3? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: The TR9714 leaves at 09:40. Sentence2: Can you please provide me with the arrival and travel time? Thank you Sentence3: Their address is saint andrew's street, and their phone number 01223334900. Sentence4: Great, thanks so much, that's all that I need! Sentence5: Okay, there are 18 in town! What part of town would you like to go to? Sentence6: The arrival time is 12:23, and it's a long trip - 163 minutes. Can I help you with anything else today? Sentence7: I'll be traveling to Cambridge and want to depart from Birmingham New Street. What are my options? Sentence8: I personally like to visit Christ's College myself. And, it's free to enter. Would that work for you? Sentence9: That sounds great. Can you give me the address and phone number? Sentence10: Thank you so much for calling Cambridge TownInfo centre! It was a pleasure to serve you, we hope you enjoy your trip! Sentence11: I need to book a train that leaves after 08:45 on Sunday Sentence12: Yes I am looking for colleges to visit in town. Sentence13: Whichever one wherever you like best please. Sentence14: I can help! Where are you traveling to? Question: Who has spoken the sentence 4? (A) User (B) System
[EX A]:
Answer: (A) User