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: Enjoy your stay in Cambridge! Sentence2: Okay well I was able to book you at The Worth House and your reference number is 86XVFEUY . Sentence3: Can you please tell me how many people will be staying and for how many nights? Sentence4: Hello, I'm looking for a guesthouse on the westside to stay. Sentence5: Yes, in the same price range please. Sentence6: Please book it for Friday,thank you. Sentence7: You are welcome. Also for your reference the Worth House does have free parking. May I help you with anything else? Sentence8: The amount of stars do not matter as long as it is in the same price range Does Worth House in the North include free parking? Sentence9: I have found one that is cheap with 4 stars, and one that is moderately priced with 3 stars? Do either of those sound appealing to you? Sentence10: Worth House in the North is 4 stars and cheap. Would you like to try it? Sentence11: Yes, 3 people for 5 nights starting on monday. Sentence12: Booking was unsuccessful. Want to try another hotel? Sentence13: Great! That's Finches Bed and Breakfast. It's located at 144 Thornton Road cb30nd. Would you like to book a stay? Sentence14: No thanks. Thanks again for your help. Sentence15: I am sorry I have no guest houses in the west. Can I look one up in another area for you? Sentence16: Are there any other places like that that also have free parking in that area? Sentence17: The cheap one with the better rating sounds appealing. Sentence18: Thanks, that's all I need. Have a nice day. Question: Who has spoken the sentence 4? (A) User (B) System
Output:
Answer: (A) User