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: I have the TR1612 that leaves friday at 9:11 and will arrive at 9:58. Would you like me to book that? Sentence2: Yes, I am also looking for a 3 star guesthouse that's moderately priced and has wifi. Sentence3: The phone number is 01223247942 and postcode is cb28rj. Can I help you with anything else today? Sentence4: Arrive by 10:45. Sentence5: You're welcome, have a great stay. Sentence6: I am traveling from Kings Lynn to Cambridge. Sentence7: What is its address? Sentence8: Yes please book for 1 person and provide me with the reference number. Sentence9: The bridge guest house. Is there anything else I can help you with? Sentence10: You have 3 choices: one in the south, one in the north, and one in the west. Would you like to book a room at one of these? Sentence11: Okay, we have 19 trains leaving on friday. Do you have any times you wish to leave and arrive by? Sentence12: I'm looking for a train that leaves on friday Sentence13: No, that should be all. Thank you! Sentence14: I have several trains leaving on that day. Where are leaving from and your destination? Sentence15: What's the name of the one in the south? Sentence16: I booked it for you. Your reference number is GWME416R . Is here anything else I can help you with today? Question: Who has spoken the sentence 12? (A) User (B) System
Answer: (A) User