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

Sentence1: You're all set! Your car type is a yellow BMW and the contact number is 07365584187. Sentence2: I'd like to leave by 08:00. Sentence3: I want to arrive by 14:00 and it doesn't matter when I leave actually Sentence4: Bye, have a great night! Sentence5: Ok, when do you want to arrive? Sentence6: Certainly, and do you know what time you would like to leave? Sentence7: Thank you so much. You have been so helpful. Goodbye. Sentence8: I need a taxi to come to rajmahal and want to go to kohinoor. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User