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: No, it's located in the centre. Sentence2: I'll be departing from the stansted airport on monday. Sentence3: Thanks for the information, that is all. Sentence4: There are a few available. I highly suggest Cambridge Artworks located on 5 Greens Road. Do you need any information? Sentence5: how about parkside pools? they're pretty fun. Sentence6: And what time were you looking to depart? Sentence7: I'm trying to go to cambridge. Sentence8: I've found TR5754 leaving stansted airport at 11:24 and arriving in cambridge at 11:52. The price is 10.10 pounds, can I book this for you? Sentence9: How about a museum? Sentence10: That won't work then. I need one in the west. Sentence11: Can I look up any attractions, taxi or anything else for you? Sentence12: Is parkside pools on the west side? Sentence13: No. I do need to find a swimming pool in the west. Sentence14: What is your travel destination so I can narrow it down to a useful schedule? Sentence15: No, that is all I need today. Thank you so much. Sentence16: Thank you for using our services. Have a good day. Sentence17: Yes, I am looking for information on train schedules for my upcoming trip. Sentence18: Where will you be departing from? Also, what day will you be traveling? Sentence19: There are no pools in the west, can I run another search for you? Sentence20: Doesn't matter, as long as I arrived by 12:45. Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System