Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: Thank you for all of your help! Sentence2: Booking was successful. Reference number is : ANH718Q1 . Is there anything else I can help with? Sentence3: Yes, I need to book it for 5 people. Sentence4: Can you help me find a guesthouse with free parking? Sentence5: Will you need anything else right now? Sentence6: Yes please book for 5 people. Sentence7: I also need a train departing from cambridge going to broxbourne. Sentence8: I have one train leaving at 9:01 that day. Would you like to book a ticket? Sentence9: Thank you, you as well! Sentence10: Thank you very much! Sentence11: The alexander bed and breakfast is a 4 star facility with internet and free parking. Their number is 01223525725. What day would you like to arrive? Sentence12: Great can you book it for 5 people for 3 nights starting monday? Sentence13: I would like to leave on Wednesday and the train should leave after 09:00. Sentence14: What day would you like to travel and when do you want to leave? Sentence15: I have booked Train TR3279 departing at 9:01. The total fee is 89.5 GBP payable at the station. Reference number is : 0G1S9EH9 . Sentence16: Definitely! Do you have a price range and/or area in mind? Sentence17: I would like the guesthouse to be in the cheap range. Sentence18: Thanks for booking with us. Have a great day! Sentence19: We have a couple of choices for 4 star ones in the center and the east. Shall i just pick one for you? Sentence20: That will be all. Thank you for all of your help. Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System