You will be given a definition of a task first, then some input of the task.
You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: No thanks I will book it. Can you help me find an expensive restaurant as well? Sentence2: No. It is in the west. Need a place in north? Sentence3: Sure thing I would suggest this place graffiti. Sentence4: what time do you want to arrive? Sentence5: I need help picking the correct train that will arrive at the time I need. Sentence6: That sounds great. My math isn't the best so please tell me what the total travel time is. Sentence7: Actually, I can't find any restaurants serving creative food. Can we try a different cuisine? Sentence8: Booking was successful. The table will be reserved for 15 minutes. Reference number is V8CR4ENN . Sentence9: The closest you could arrive on Monday is the 14:09 train that will get you there by 16:30. Does that sound good? Sentence10: That is all. Have a nice day. Sentence11: I am leaving from Leicester and going to Cambridge. Sentence12: I would like to arrive by monday at 16:30. Sentence13: The travel time is 105 minutes. Shall I book it? Sentence14: I have one option for you that is called The City Stop Restaurant and it is expensive. Does this interest you? Sentence15: Yes, please. I'd like something with some creative food. Sentence16: I need a table at 20:15 on Monday. Sentence17: Make the reservation for 2 people please. Sentence18: How about european food please? Sentence19: On what day would you like to dine? Sentence20: Can you book a table for 2? Sentence21: How many people will be dining? Sentence22: What are your departure and destination sites? Sentence23: Is it in the North area? Sentence24: Great, you have one too! Question: Who has spoken the sentence 4? (A) User (B) System
Output:
Answer: (A) User