Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: What about the Gonville Hotel? It is an expensive hotel in the centre of town. Sentence2: Actually, I need it to be a hotel, not a bed and breakfast. Sentence3: Hotel Du Vin and Bistro serves European food and is moderately priced. Does this sound good to you? Sentence4: No. I just need it to be for three people, for three nights. Sentence5: What kind of moderately-priced restaurants are there in the center of town, then? Sentence6: It has been my pleasure. Have a nice day. Sentence7: The car is a black audi and the contact number is 07306125704. Is there anything else I can help you with today? Sentence8: No, I think that's all. You have been very helpful. Sentence9: We've got 21 moderately-priced restaurants in the centre. There are Asian Oriental, British, Chinese, European, Gastropub, International, Italian, Lebanese, Modern European, Spanish, and Turkish options. Do any of those interest you? Sentence10: Your booking is complete, reference number is AEDKGYBD . Anything else I can help you with? Sentence11: Yes please, could you find a hotel that offers free wifi in the same part of town as the restaurant? Sentence12: I am looking for a restaurant in Cambridge that serves south indian food. Sentence13: I am showing a total of five results that match your criteria. May I suggest the four star Alexander Bed and Breakfast, located at 56 Saint Barnabas Road? Sentence14: No thanks. How about a moderately priced modern European restaurant? Sentence15: Could I please get the car type and contact number of the taxi? Sentence16: I'm also looking for a taxi that arrives at the booked time of the restaurant. Sentence17: Good. I would like to try Asian Oriental then. Sentence18: The Yippee noodle bar meets your criteria. Would you like me to book that for you? Sentence19: Alright, I have a cab booked for you from the Gonville Hotel arriving at Hotel Du Vin and Bistro by 15:15. Anything else I can do for you? Sentence20: Sure thing! Your table is booked, and your reference number is SQ8N4IJX . Is there anything else I can assist you with today? Sentence21: I am sorry there are no restaurants in the are that match that description. Sentence22: There are 5 options that fit your criteria. Do you have a price range in mind or any other specifications? Sentence23: That sounds good can you book it for 3 nights for 3 people on saturday? Sentence24: Yes, thank you. Will you please make a reservation at the restaurant for 3 people on Saturday at 15:15 and provide me with the reference number? Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System