Given the task definition and input, reply with output. You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.

Sentence1: Rosa's Bed and Breakfast is located at 53 Roseford Road. Would you like me to make a reservation for you? Sentence2: I'm hoping to find Rosa's Bed and Breakfast. Sentence3: Alexander bed and breakfast was able to be booked reference number is YUX0ZQKU . Sentence4: Yes. I need a reservation for 3 people for 2 nights starting from Saturday. Sentence5: Thank you for using our system today! Sentence6: Thanks, that's all I need. Have a nice day. Sentence7: Yes can you find a different hotel in the same price range? Sentence8: Yes, try another area, please. Sentence9: I am sorry there are no others in that price range in that area. Would another area be okay? Sentence10: The booking was unsuccessful. Is there another hotel you would like me to look into? Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User