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: Thank you for contacting Cambridge TownInfo centre. Have a nice day! Sentence2: Yes, I will be leaving at 16:30 from Bedouin. Sentence3: A grey toyota will be picking you up. Do you also need the contact number? Sentence4: I need a 16:30 taxi. Sentence5: I have booked your taxi Sentence6: Yes, please. I need it in case there is a problem. Sentence7: I'd be happy to help with your request, will you be leaving at 16:30 and what is your departure site? Sentence8: I am going to london liverpool street train station. Sentence9: No problem.The contact number is 07357977369. Can I help with anything else? Sentence10: Great. And what is your destination? Sentence11: No thank you. Sentence12: Thank you very much. Question: Who has spoken the sentence 3? (A) User (B) System
Answer: (B) System