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: Please. I need a reservation for 8 people at 12:45 on Sunday. Sentence2: Booking was successful. Reference number is : EI63A77M . Is there anything else I can help you with? Sentence3: no, it should be a guesthouse though. Sentence4: Yes for 8 for 3 nights starting sunday Sentence5: There is only one Korean restaurant in all of Cambridge, but it's expensive, not moderate. Sentence6: la tasca is a spanish restaurant located in the centre. Can I book that for you? Sentence7: I'm hoping to find a moderately priced korean restaurant. Sentence8: Yes, I would also like a hotel with free wifi in the moderate price range. Sentence9: No that is all the help I need today. Thank you Sentence10: Can you run one more search for korean cuisine in the centre area please? Sentence11: Okay what about spanish cuisine then? Sentence12: Alright, the table is booked for 12:45 and will be reserved for 15 minutes and your reference number is GIBFWDNM . Can I help you with anything else? Sentence13: Do you have an area in mind? Sentence14: I'm sorry, we don't have anywhere that matches that description. Is there somewhere else I can try and find for you? Sentence15: a and b guest house is in the moderate price range. Should I book it? Sentence16: Sure thing. Enjoy your stay Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User