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

[EX Q]: Sentence1: I'll be leaving from Leicester and want to go to Cambridge. Sentence2: Booking was successful, reference number is YN5MH1ZN . Anything else I can help you with? Sentence3: Where are you departing from and what is your destination? Sentence4: I need a hotel in the north that has free parking. Sentence5: There are 11 different hotels. To help narrow it down, can you tell me if there is a price range you prefer? Sentence6: All right. I need a booking for six, please, and the reference number. Sentence7: Yes it is. Sentence8: There are 91 trains leaving Leicaster to Cambridge after the specified time. How does Friday 11:09 sound? Sentence9: No thank you that will be all. Thank you for your help in booking my trip and stay! Sentence10: How about the Acorn guest house on 154 Chesteron Road? It's a moderate price range guesthouse that is rated 4 stars with free parking and wifi. Sentence11: Perfect. I'd like to book a 5 night stay for the six of us. Sentence12: Great. Is this hotel stay also starting on Friday? Sentence13: No problem! You have a wonderful day! Sentence14: I'm looking for a train leaving after 10:30. Sentence15: No not really, I would prefer a guesthouse type of hotel with free wifi though. Sentence16: I was able to book the train for you for 6 people. The reference number is 7QAMUGHQ . Do you need anything else? Question: Who has spoken the sentence 15? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: Does it have four stars? Sentence2: Not yet, but can you tell me what time the train arrives in Ely please? Sentence3: acorn guest house is located in 154 chesterton road should i book it for you? Sentence4: I would like to leave on Tuesday after 18:00. Sentence5: It arrives by 20:07! Anything else love? Sentence6: TR5511 leaves Cambridge for Ely at 20.07. Do you need tickets? Sentence7: I've booked your stay at the Acorn Guest House, and your reference number is IT07BRTC . Sentence8: The trip will last 17 minutes. Is there anything else you would like to know? Sentence9: Do you know what day or time you want to leave? Sentence10: Thank you for using Cambridge TownInfo centre. Please consider us for your future travel needs. Sentence11: I need some lodging accommodations. It needs to have free parking and Internet please! Sentence12: I would like someone to book me a place with free parking and internet. Sentence13: That should do it. Thanks so much for your help! Sentence14: I found 29 hotels matching your request. What price range and area of town would you prefer? Sentence15: Thanks a lot. Can you also help me find a train going to Ely? Sentence16: Yes. Please book it for 2 people for 4 nights starting Friday. Sentence17: Yes it does. Shall I book? Sentence18: What is the total travel time on that time? Question: Who has spoken the sentence 15? (A) User (B) System
[EX A]: Answer: (B) System

[EX Q]: Sentence1: Do you have any 3 star hotels available? Sentence2: There are no matches, would you like to check other locations? Sentence3: The soul tree nightclub is quite lively. Their postcode is cb23qf and their phone number is 01223477900. Sentence4: Thanks for recommending the Guest House. I am also looking for some town nightlife, especially a nightclub. Sentence5: I have no preference. Can you suggest one and give me their postcode and phone number? Sentence6: There are no 3 star hotels in the north with a moderate price? Sentence7: There are two hotels available; the Ashley Hotel and the Lovell Lodge. Both offer internet and parking and are 2 star hotels. Do you have a preference? Sentence8: Unfortunately, no. I do happen to have 2 guesthouses though. Both are moderate pricing and 3 stars. Are you interested in one of those? Sentence9: We have 6 nightclubs in town. Would you prefer to visit the centre or the south? Sentence10: Yes, please. Can I get a room for 4 people? We'll arrive on Wednesday and stay 5 nights. Sentence11: Hello, can you recommend a moderately-priced hotel in the North part of town, please? Sentence12: Done! You have a reservation at the Alpha-Milton Guest House. Your reference number is 9SA494XR . Can I help you with anything else? Sentence13: Thank you for using Cambridge TownInfo centre. Have a great day! Sentence14: Great, thank you! That's all for today! Bye bye! Question: Who has spoken the sentence 13? (A) User (B) System
[EX A]:
Answer: (B) System