You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: Thank you. Enjoy your trip. Sentence2: The first train leaves on Friday at 05:11 and arrives at 05:58. Should I book it for you? Sentence3: No, not at this time. Thank you, good bye. Sentence4: Hello, I am looking for a train heading to Cambridge and I will be departing from Kings Lynn. Question: Who has spoken the sentence 3? (A) User (B) System
Answer: (B) System