Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: Goodbye. Sentence2: Goodbye. Sentence3: No, thank you. Sentence4: good bye. Sentence5: Thanh binh serves vietnamese food. They are located at 17 Magdalene Street City Centre. Would you like more information? Sentence6: I am looking for a restaurant serving vegetarian food. Sentence7: we do not have any restaurant serving vegetarian food. Can I help you with anything else? Sentence8: Can you look for Vietnamese restaurants then? Question: Who has spoken the sentence 4? (A) User (B) System
A:
Answer: (A) User