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

Sentence1: They serve European food then? Sentence2: It's an expensive european place in the centre at St. Michael's Church Trinity Street City Centre cb21su with phone 01223309147. Would you like to book a table? Sentence3: Yes michaelhouse cafe serves european food. Would you like any other information about this resturant? Sentence4: I managed to book you for a taxi at that time. It will be a white Audi and the contact number is 07947363494. Is there anything else? Sentence5: I actually have 4 different ones. If I may suggest one, the Mumford Theatre is new and really fun. Sentence6: Hi, I need help planning a trip to Cambridge. I'd like to go to the theatre while I'm in town, and I'll be in the city centre. Is there one there? Sentence7: Thanks. I also need information about a specific restaurant called michaelhouse cafe. What can you tell me about it? Sentence8: That sounds great, what's their phone number? Sentence9: That will be all, thank you and goodbye. Sentence10: Their number is 08451962320 Sentence11: Thank you for using our service. Have a great day. Goodbye. Sentence12: No, that's perfect, but I will need a taxi to go from Mumford Theatre, leaving by 12:00, to go to St. Michael's Church Trinity Street City. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User