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: Thank you for your help Sentence2: The phone number is 01223256233. Sentence3: You are more than welcome! Sentence4: I am injured and need a hospital with a cardiology department. Sentence5: The Addenbrookes Hospital located at Hills Rd, Cambridge has a cardiology department. Would you need to book an appointment? Sentence6: I would like to have the phone number. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User