Given the task definition and input, reply with output. You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: No they serve Chinese food. Would you like me to search for Italian food? Sentence2: I also want to eat at a cheap place in the center area. Sentence3: Yes that would be great. I'd love for you to book me a table for 1 person at 18:45 on Saturday. Sentence4: I would like one located in the centre of town if possible. May I please have the phone number? Sentence5: I'm looking to go to a park, can you suggest any? Sentence6: Booking was successful. The table will be reserved for 15 minutes.Reference number is : ZLQ7OVEV . Sentence7: I have the cambridge university botanic gardens. There phone number is 01223336265. Can I help you with anything else today? Sentence8: There are 5 different parks in the city. What area of the city are you wanting to visit? Sentence9: Thank you, that's all I need today. Sentence10: I would suggest charlie chan Sentence11: Do they serve Italian food? Sentence12: Thank you; please consider us for your future travel needs. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User