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

Sentence1: Yes, please. For 5 people at 14:00 on monday. Sentence2: The camboats are located in the east, how's that? Sentence3: I do not have information on the fee. Sentence4: Ok, thank you. I'm also looking for a restaurant called don pasquale pizzeria. Sentence5: Your booking was successful with reference number 1RF57JD7 . Oh, by the way, your table will be reserved for 15 minutes. Enjoy! Sentence6: Have a lovely stay in Cambridge! Sentence7: Thank you for the reference number. Goodbye! Sentence8: That might be good. What is the entrance fee? Sentence9: Don Pasquale is in the centre. Would you like me to make a reservation? Sentence10: I'm looking for some boats in the East, actually. Question: Who has spoken the sentence 7? (A) User (B) System
Answer: (B) System