You will be given a definition of a task first, then some input of the task.
You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: Unfortunately I need to leave after 09:30, is there one available then? Sentence2: Thank you for using our system! Sentence3: By travel time, I mean the duration of the train trip. Sentence4: That will probably work fine. Can you tell me the travel time for that train? Sentence5: No, that's not necessary. I can book it later. Thanks. Have a good day. Sentence6: The first train of Sunday leaves at 11:21 and arrives by 12:10. Does that meet your requirements? Sentence7: Thanks again. Goodbye! Sentence8: Thank you! Goodbye. Sentence9: I am leaving out of Cambridge. I need the ticket for Sunday. Sentence10: Sure thing, train TR8464 leaves at 11:21. Will that work? Sentence11: TR5390 is the first train of the day leaving at 5:21 would that work for you? Sentence12: I'm sorry. That comes out to a 49-minute train ride. Does that sound agreeable to you? Sentence13: Yes that will be fine. Sentence14: I need a train to Stevenage. Sentence15: Am I booking one ticket? Sentence16: Absolutely. From where would you like to depart? Question: Who has spoken the sentence 6? (A) User (B) System
Output:
Answer: (A) User