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

Sentence1: I have Gonville Hotel in centre area or The Lensfield hotel in the south area. What is your preference? Sentence2: I'm also looking for a hotel to stay in. Preferably a 3 star one. Sentence3: I'm planning to leave on Thursday. Sentence4: Which day are you planning to travel? Sentence5: The Gonville would be great, could you get me the phone number, price range, and postcode? Sentence6: They are in the expensive range, located on gonville place, postal code cb11ly, they are reachable at 01223366611, may I assist with anything else? Sentence7: There are several trains leaving Norwich, what day are you leaving and where are you going? I also need the time you want to leave or arrive. Sentence8: Yes the departure time is 15:16. I booked you for 8 on Train ID TR8040. The Reference number is : 1HY8AJ7Y . Sentence9: No thank you for everything. Sentence10: You are welcome. Have a good evening. Sentence11: I want a train leaving from norwich. Sentence12: As long as you mean a 15:16 departure, I'll take 8 tickets, please. Sentence13: I have a 5:16 departure to Cambridge that arrives at 16:36. Would that do? Sentence14: What area of town would you like? Do you have a price range in mind? Sentence15: I would like to leave after 14:30 and go to Cambridge, please. Sentence16: I don't have a preference for either, but I'd like it to be in the type of hotel. I'll also need free parking. Question: Who has spoken the sentence 15? (A) User (B) System
Answer: (B) System