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: I'm leaving from gallery at twelve a high street. Sentence2: I need a taxi to take me to rajmahal. Sentence3: No, that's it. Thank you so much! Sentence4: And when would you like to leave? Sentence5: Thank you for your help. Sentence6: You're quite welcome. Is there anything else I can assist you with? Sentence7: I have you booked in a grey audi. Sentence8: Where will you be departing from? Sentence9: It was my pleasure. Have a nice day. Sentence10: Contact number is 07270553802 Sentence11: Thank you, can you give me the contact number please? Sentence12: I would like to leave after 3:45. Question: Who has spoken the sentence 4? (A) User (B) System
Answer: (A) User