Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: Thank you. That is all I need. Sentence2: Can you help me find a place to stay Sentence3: I'm looking for a Chinese restaurant on the south side of town. Sentence4: Great your reference number is 4U18B867 Sentence5: Yes please. Let's try the other one you mentioned. Sentence6: All right, a white ford will arrive by 17:30. The contact number is 07655989652. Sentence7: Book me a table for 7 on Thursday at 17:30 and send me a reference number. Thank you. Sentence8: Thank you for using this system! Sentence9: Would you like to book cheap or expensive? Sentence10: No problem, there's the aylesbray lodge guest house which is also in the south area. It's moderately priced, four stars, with parking and internet. Would you like me to book this for you? Sentence11: I don't care what price range it is in. I will need a reference number please for the reservation. Sentence12: Yes I need to book it for 7 people, for 4 nights starting thursday, can I get the reference number? Sentence13: Ok, I've booked a table for 7 at 17:30 on thursday at the good luck chinese food takeaway. Your reference number is LA1YYDOO . Sentence14: Thank you. I will also need a taxi so that I can commute between these two locations and I need it to arrive at 17:30. Sentence15: There are 2 expensive and 1 cheap restaurant matching your criteria. Which price range do you prefer? Sentence16: Let's decide on the lucky star. Unfortunately, that appears to already be booked. Do you want to try one of the others? Question: Who has spoken the sentence 4? (A) User (B) System
A:
Answer: (A) User