Definition: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Input: Sentence1: Sure. Can you give me the names and addresses of the other 3 as well? Sentence2: Train TR7900 leaves cambridge for birmingham new street monday at 16:01. Your reference number is OCF8O3GJ . Sentence3: I am looking for a train. The train should leave on monday and should go to birmingham new street Sentence4: There are several trains available. Are you able to provide a specific time? Sentence5: Can you help me find a theatre in the centre of town? Sentence6: Have a great day! Sentence7: cambridge arts theatre is at 6 saint edward's passage, mumford theatre is at anglia ruskin enterprise, east road; and the cambridge corn exchange is at wheeler street. Sentence8: What is your departure time and location? Sentence9: Ok, great. That's all I needed. Thank you for all of your help! Sentence10: No, the first train after 15:15 will work. I need to book the trip for 8 people, and please include my reference number. Sentence11: Sure, there is cambridge arts theatre, it is located at 6 saint edward's passage. There are 3 others if you would like information on them as well. Sentence12: Leaving Cambridge going to Birmingham New Street on Monday any time after 15:15. Question: Who has spoken the sentence 4? (A) User (B) System
Output:
Answer: (A) User