You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Q: Sentence1: Is there a certain area of town you would like to be in? Sentence2: No thank you. I would like to know the arrival time, though. Sentence3: It doesn't matter, just so it leaves after 15:00. I'll just need the train id and arrival time please. Sentence4: I'll be traveling on Monday and I would like to leave after 15:00. Sentence5: No thanks. That gives me all I need. Take care. Goodbye. Sentence6: Thanks. Can you also find a museum ? Sentence7: What time do you need to arrive by? Sentence8: The arrival time is 16:07. Sentence9: Thank you for allowing me to assist you today. Sentence10: There are 70 scheduled trains on that route. Do you have a day or time you wish to travel? Sentence11: No, whatever your recommendation is. I will just need the area it's in and the entrance fee please. Sentence12: people's portraits exhibition at girton college in the west is very interest, the entrance fee is free. Do you need more info? Sentence13: the TR7177 leaves at 15:50, do you want tickets? Sentence14: I'd like details about trains leaving from Cambridge and going to Ely. Question: Who has spoken the sentence 13? (A) User (B) System
A:
Answer: (B) System