Detailed Instructions: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Q: Sentence1: The Lucky Star is cheap and serves Chinese food. Sentence2: There are a total of 21 hotels in cambridge with a 4 star rating. Would you prefer a certain price range or location? Sentence3: Great! What day would you like to book? Anything else you want to share? Sentence4: Is there anything that is cheap, and in the south that could serve Singaporean food? Sentence5: OK, a guesthouse will be fine. Sentence6: You're welcome! Have a great trip! Sentence7: I also am looking for a hotel with a 4 star rating. Sentence8: I was able to book that for you. The car type is a White Honda and the contact number is 07321469386. Is there anything else I can help with? Sentence9: Can you book me a taxi to bring me between the two? I am wanting to leave the hotel by 16:45. Also can I have the contact number and car type? Sentence10: Where is a good cheap Singaporean place to eat? Sentence11: I am looking for a cheap place in the south. Sentence12: Great thank you that's all that I needed today. Sentence13: There are no hotels meeting those criteria in the south however Rosa's Bed and Breakfast guesthouse with 4 stars priced cheap is available. Sentence14: My system isn't showing anything, do you have a particular name or any alternative type restaurants you would like me to try? Sentence15: The phone number is 01223244277, address is Cambridge Leisure Park Clifton Way Cherry Hinton, and postcode is cb17dy. Sentence16: Sorry there is not restaurant matching your request available. Would you like to select a different food type to see what we can find? Sentence17: That'll be great. Can I get the phone number, address, and postcode to that please? Sentence18: Yes, can you find me a cheap place to eat serving chinese food? Sentence19: The phone number for Rosa's Bed and Breakfast is 01223512596 and the postcode is cb22ha. Can I help with anything else? Sentence20: I don't wish to book. Can I just get the postcode and phone number? Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System