You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Q: Sentence1: Booking was successful for the bridge guest house. Your Reference number is : LBEOV690 . Sentence2: Yes please. Which is the cheapest? Sentence3: Thank you. Have a nice day. Sentence4: No. I would like to make a reservation for Wednesday for 3 nights and 8 people. I will also require a reference number. Sentence5: I was unable to book your stay at any of the three hotels. Would you like to change the length of your stay or change the day? Sentence6: There are 2 hotels with a 3 star rating and free parking. Would you like to stay in the centre or south? Sentence7: Sorry, I was mistaken. There are 3 guesthouses matching your request. One each in the south, north, and west. Would you like to book one? Sentence8: Thank you. Have a nice day. Sentence9: Can you please try a 2 day stay. Sentence10: I can only tell you they are all in the moderate price range. Do you have any other preferences? Sentence11: I am looking for a hotel with a 3 star rating and free parking Sentence12: Either is fine. I'd like a guesthouse. Question: Who has spoken the sentence 5? (A) User (B) System
A:
Answer: (B) System