Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: I need a taxi from london kings cross train station to the gonville hotel. Sentence2: That's okay, thanks so much for your help. Have a good day now, bye! Sentence3: Tell the customer what time the train departs from London kings cross train, and possible arrival time to gonville hotel. Sentence4: You are welcome. Bye. Sentence5: I'm sorry about that. I have booked you a black audi arriving at the hotel by 23:00. The contact number is 07582132009. Sentence6: Um what? I need to arrive by 23:00. Can you help or not? Question: Who has spoken the sentence 4? (A) User (B) System
A:
Answer: (A) User