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

Sentence1: What time will that be? Sentence2: Going back to the train info, how long is the ride from birmingham new street to Cambridge? Then, I want to book the Anatolia restaurant for Friday, also. Thank you. Sentence3: Alright, your train ticket has been purchased and the reference number is 41YRXR8G . There are also 2 moderately priced Turkish restaurants in the centre of town, the Anatolia and Efes Restaurant. Sentence4: I have many trains that can get you to your destination. What day would you be traveling? Sentence5: I need a train that leaves after 15:00 on Friday. Sentence6: What train can I take to get to Cambridge from Birmingham New Street? Sentence7: I need to leave on Friday. Sentence8: Can you give me the reference number? Sentence9: I have not found any train that matches your info. Can I help you with anything else? Sentence10: I will be going to cambridge. Sentence11: 1 ticket please. I am also looking for a moderately priced turkish restaurant located in the centre. Sentence12: Certainly, the number is KRE2S785 . Can I be of further assistance? Sentence13: You're welcome. Goodbye! Sentence14: Where will you be going? Sentence15: The train trip is 163 minutes. How many people will be in your party for the restaurant? Sentence16: It would be 2 people. Sentence17: No, that is all I need for now. Thanks so much. Bye. Sentence18: ok I have reserved a table for 2 at the Anatolia Restaurant for 19:00. Is there anything else I can do for you? Sentence19: I'd like the table reserved for 19:00. Sentence20: How about TR9756, it leaves at 15:40. How many tickets would you like Question: Who has spoken the sentence 13? (A) User (B) System
Answer: (B) System