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

Sentence1: I'm looking for a moderately priced restaurant to eat at in the north. Sentence2: Then booking was unsuccessful. Would you like me to try the Indian restaurant? Sentence3: I would like a table for 8 people at 17:30 on Wednesday Sentence4: If you tell me a day and a time you would like to reserve, I can book that for you. Sentence5: No problem. I hope you have a great day. Good-Bye! Sentence6: Thank you so much for your help. Sentence7: It's booked, your reference number is 5YBVERXA . Sentence8: Chinese would be great! Sentence9: Okay, that sounds good. I'll need a reference number. Sentence10: I've found a Chinese restaurant and an Indian restaurant. Which one do you prefer? Question: Who has spoken the sentence 9? (A) User (B) System
Answer: (B) System