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: The TR9714 leaves at 09:40. Sentence2: Can you please provide me with the arrival and travel time? Thank you Sentence3: Their address is saint andrew's street, and their phone number 01223334900. Sentence4: Great, thanks so much, that's all that I need! Sentence5: Okay, there are 18 in town! What part of town would you like to go to? Sentence6: The arrival time is 12:23, and it's a long trip - 163 minutes. Can I help you with anything else today? Sentence7: I'll be traveling to Cambridge and want to depart from Birmingham New Street. What are my options? Sentence8: I personally like to visit Christ's College myself. And, it's free to enter. Would that work for you? Sentence9: That sounds great. Can you give me the address and phone number? Sentence10: Thank you so much for calling Cambridge TownInfo centre! It was a pleasure to serve you, we hope you enjoy your trip! Sentence11: I need to book a train that leaves after 08:45 on Sunday Sentence12: Yes I am looking for colleges to visit in town. Sentence13: Whichever one wherever you like best please. Sentence14: I can help! Where are you traveling to? Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User