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

Sentence1: That is all I need, thank you! Sentence2: Where will you leave from? Sentence3: I'm leaving from birmingham new street train station. Sentence4: Booking completed! Booked car type : red lexus Contact number : 07427709999 Sentence5: I need a 04:00 taxi at the Cambridge Lodge Restaurant. Sentence6: You're quite welcome. Thanks so much for using the Cambridge TownInfo Centre. Have a great day! Goodbye. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User