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: Can you get me there a little bit earlier? Sentence2: Sure, Can I have a reference Number? Sentence3: Which of those have free wifi? Sentence4: Actually, I change my mind. I will take care of the booking later. Thanks for your help. Goodbye. Sentence5: I need some more information first. What day will you be checking in on, and how many days will you be staying for? And how many people? Sentence6: Okay, I have you booked for train TR5910. The total fee is 80.8 GDP. Is there anything more I can do for you? Sentence7: There will be 8 of us. Sentence8: There are 5 different options that fit that criteria, 2 in the east, 2 in the north, and one in the city centre. Would you like to hear more about these? Sentence9: I also need a guesthouse for 8 and needs to be a 4 star Sentence10: How about 05:24 that is the earliest, how many tickets please? Sentence11: How about Allenbell? Sentence12: Thank you contacting us, it was a pleasure to help. If you need any assistance feel free to contact us again, goodbye. Sentence13: There are actually 18 different options to choose from. Is there a certain part of the city you'd like to stay in, or a particular price point? Sentence14: i need a train from stansted airport to cambridge Sentence15: I need to get there by 20:30 on Wednesday. Sentence16: You could grab the TR3828 leaving stansted airport it will get you there by 09:52. Sentence17: Any price point is fine as long as it is 4 star and has free parking. Sentence18: What day and approximately what time will you be traveling to Cambridge? Question: Who has spoken the sentence 13? (A) User (B) System
Output:
Answer: (B) System