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

Sentence1: Yes, I need a booking for 7 people and the reference number. Sentence2: Yes, hello. I need a train departing from cambridge and should go to stansted airport. Sentence3: Sure thing, what day will you be leaving? Sentence4: I will be leaving on Sunday Sentence5: The total is 56.56 GBP and can be paid at the station. the reference number is Y1MGNCV3 Sentence6: TR5529 leaves at 5:40 and arrives at 6:08, will this work for you? Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User