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: Yes please book it for one person for 2 nights starting friday. Sentence2: Sure. Your booking was successful and I have a reference number for you. It is IBDDDIAJ . Sentence3: Thank you for using our service today. Sentence4: I'm looking to get some info on a hotel called cityroomz. Sentence5: Thank you very much for your help. Have a great day. Sentence6: I've found it, would you like me to book it for you? Question: Who has spoken the sentence 3? (A) User (B) System
Answer: (B) System