You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Q: Sentence1: Yes, I'm also interested in finding some kind a multiple sports place to go while I'm in town. Is there anything like that? Sentence2: It is located at 144 thornton road postcode cb30nd and the phone number is 01223276653. Sentence3: Thank you, that is all I need today. Sentence4: How can I book a room? Sentence5: Where is Finches Bed and Breakfast located? Sentence6: Their phone number is 01223576412 and they're located in the east. Sentence7: Your booking was successful. Your reference number is 1KB3H7VC . May I help you with anything else? Sentence8: You are most welcome, have a wonderful day! Sentence9: I need to book it for 3 days starting on Wednesday. There are 6 people in my party. Sentence10: Please, what's their phone number and what area are they in? Sentence11: I'd be happy to do that for you, if you want to give me your details. Sentence12: There is the Cherry Hinton Village Center in the east. Would you like more information? Question: Who has spoken the sentence 7? (A) User (B) System
A:
Answer: (B) System