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

Sentence1: The amount of tickets today is not important I just want to make sure that I leave on Saturday and if I could get an arrival time please Sentence2: The postcode is cb21jf. Is there anything else I can help you with today? Sentence3: Yes, two tickets please. Sentence4: Train TR5413 arrives at 24:44 OR 00:04 on Sunday. Would you like to book it now? Sentence5: Your booking has been successful! The total fee is 120.16 GBP and the reference number is OYUCGOSD . Do you need help with anything else? Sentence6: TR5413 leaves Cambridge at 22:01 and costs 60.08 pounds. How many tickets do you need? Sentence7: What about park attractions? Sentence8: I found the Cambridge University Botanic Gardens on Bateman Street. Sentence9: OK. Can I have the postcode? Sentence10: I'm looking for entertainment attractions in the centre of town. Sentence11: That was all for today. Thank you very much and have a good evening. Sentence12: You're welcome. Good-bye. Sentence13: I am also looking for a train to go to Birmingham New Street and to leave after 21:30. Can you book me a train that leaves on Saturday? Sentence14: Cambridge University Botanic Gardens cost 4 pounds, and is a park type attraction. Sentence15: What attractions are at the Botanic Gardens? Is there a cost associated with the Gardens? Sentence16: There doesn't seem to be anything matching your specifications. Question: Who has spoken the sentence 6? (A) User (B) System
Answer: (A) User