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: Yes, it is. It's located on 154 chesterton road, cb41da. Would you like a room? Sentence2: I would like to leave after 15:15 on Thursday. Sentence3: Have a nice day, goodbye! Sentence4: We have a train departing Cambridge at 15:50, arriving at Ely at 16:07. Would you like me to book a reservation? Sentence5: They do indeed provide complimentary Internet access. Would you like to make a reservation? Sentence6: Your booking was successful. The total fee is 8.8 GBP payable at the station. Your reference number is H0BMD920 . Sentence7: Just one more question: Is it in the moderate prince range? If so, please give me their address. If not, I need something moderately priced. Sentence8: Yes that works great. Can you book 2 tickets for that train and give me the reference number? Sentence9: Great. That's all I needed. Thank you. Sentence10: No thanks. Not at this time. I would appreciate some help finding a train to get me to Ely though. Sentence11: Does that include free wifi? Sentence12: Can you tell me where you will be leaving from and on what day and time? Sentence13: I like acorn guest house. Need me to book a room? Sentence14: I am looking for a hotel to stay in with a 4 star rating that is in a guesthouse style. Question: Who has spoken the sentence 4? (A) User (B) System
Output:
Answer: (A) User