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

Sentence1: Thank you so very much. I am done. Sentence2: You're welcome. Have a good time! Sentence3: You are booked for a blue bmw with the contact number 07889414601. Sentence4: I need to book a taxi to take me to Williams Art and Antiques. I need to leave after 24:30. Sentence5: I'll be leaving from vue cinema. Sentence6: No problem - where should I have them pick you up? Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User