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

Sentence1: Do you have any information on the Addenbrookes Hospital? Sentence2: The main hpospital number is 0122324515. The number for their gastroenterology department is 01223274284. Sentence3: Yes, the hospital is located on Hills Rd, Cambridge. Would you like the phone number? Sentence4: You are welcome. Thank you for calling Cambridge TownInfo centre. Goodbye. Sentence5: Thanks, what is the postcode? Sentence6: No that's it for now, I appreciate it. Goodbye! Sentence7: The postcode is CB20QQ. Do you need any further assistance? Sentence8: Yes I need to know if they have a gastroenterology department. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User