You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Q: Sentence1: If you are sure you do not need anything? Sentence2: No, thank you. That was all I needed. Thanks. Bye. Sentence3: Yes, a table for 6, please. Sentence4: little seoul is found in the center of town and is in the expensive price range. could you like a reservation? Sentence5: I would also like to find a korean restaurant Sentence6: Hello, are you still there? You said that you would reserve it but never did anything, it has been 55 minutes. Sentence7: That's alright. I need my table to be booked on Sunday. Sentence8: Booking was successful. The car will be a white Toyota and the contact number is 07225283033. Is there anything else I can help you with? Sentence9: We would like 18:45 on sunday for 6 people. I'll need a taxi to go between the two places by the booked time. Please provide contact number and car type. Sentence10: Booking was successful. The table will be reserved for 15 minutes. Reference number is : U9WFNBHE . Which direction will you need the taxi for? Sentence11: Oh, I'm sorry about that. Please excuse me. What day would you like for the reservation to be made? Sentence12: No, actually it doesn't matter. Can you suggest one and provide me the postcode? Sentence13: I'll need to go between the swimming pool and the restaurant. Sentence14: I will reserve that for you now. Sentence15: I'm looking for a swimming pool in town. Sentence16: Yes, the Jesus green outdoor pool get the most consistently positive feedback, their postal code is cb43px, can I help with anything else? Sentence17: There are four swimming pools in Cambridge. Did you want one in a particular part of town? Sentence18: I need more information on the time for the booking. Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System