Given the task definition and input, reply with output. You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: Sorry there is not. How about another choice of food ? Sentence2: Leaving Cambridge to London kings cross and arrive by 19:45. Sentence3: I have a train departing Cambridge at 17:00 and arriving at London Kings Cross at 17:51. I don't have a later arrival time on Tuesday, unfortunately. Sentence4: TR0315 arrives at 13:51. is that fine with you? Sentence5: Definitely! Can you give me some more specifics so I can help? Sentence6: how about chinese? Sentence7: I am going to London kings cross. Sentence8: There aren't any Polish restaurants in the centre, are there? Sentence9: We have many Chinese restaurants! What's your price range? Sentence10: No. thanks. I don't need to book it right now. Sentence11: Ok, on what day will that be? Sentence12: It leaves Cambridge at 13:00. Sentence13: And what is your arrival destination and time of travel? Sentence14: Great! Thank you for calling and have a great trip! Goodbye. Sentence15: I'm not fussy about price, pick one for me and give me the address please, I'm starving! Sentence16: Is there anything else I can help you with today? Sentence17: I need to leave on Tuesday. Sentence18: Time I leave does not matter I just need it to arrive by 19:45. Sentence19: Alright. Could you please provide me with the train ID and the travel time? Sentence20: No, thank you. I have everything I need. Goodbye. Sentence21: Rice house is located at 88 Mill Road City Centre. Would you like for me to book a reservation? Sentence22: Just the address is all I needed for now. But could you also help me find a train? Sentence23: what is its departure time? Sentence24: That is TR0945. The train departs cambridge at 17:00 and arrives in London Kings Cross at 17:51. The travel time is 51 minutes. Can I book it for you? Question: Who has spoken the sentence 13? (A) User (B) System
Answer: (B) System