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

Sentence1: It doesn't really matter. What's your recommendation? Sentence2: There are 44 attractions in the centre of town. What kind of attraction do you want to visit? Sentence3: The post code is CB21SU. Do you need anything else? Sentence4: Cambridge Contemporary Art, what's their post code? Sentence5: I want to find some good places to go in the centre of town. Sentence6: Thank you for your help! Sentence7: Holy Trinity Church is popular for its architecture. Christ's College finds people touring the campus. Or, Cambridge Contemporary Art is a free museum. Any of those interest you? Sentence8: My pleasure! Have a good day! Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User