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

Let me give you an example: Sentence1:i need a place to dine in the center thats expensive Sentence2: I have several options for you; do you prefer African, Asian, or British food? Sentence3: Any sort of food would be fine, as long as it is a bit expensive. Could I get the phone number for your recommendation?Question: Who has spoken the sentence 2? (A) User (B) System
The answer to this example can be: Answer: (A) User
Here is why: The sentence 1 is said by a user because the intent of it says that the information has to be gathered from the system

OK. solve this:
Sentence1: I need reservations for the same group of people at 17:00 on the same day. Sentence2: No problem. I've got your taxi booked. Anything else? Sentence3: Booking was successful! Your reference number is 6ZPBNFD5 . Sentence4: The booking was successful for 2 nights at the Acorn Guest House for one person. Your Reference number is L55JCSVU . Do you need anything else? Sentence5: I hope you have a very pleasant stay in our town! Sentence6: I meant to say I need to commute between the hotel and the restaurant. Sentence7: I think that would be great. May I please book that guest house for 2 nights starting from Friday for 1 person? Sentence8: Yes I would like it to be moderately priced. Thank you. Sentence9: Can I have the contact number and car type? Sentence10: Can you also look up the sitar tandoori restaurant? Sentence11: Booking completed! Booked car type : grey bmw Contact number : 07853122848 Can I help you with anythign else? Sentence12: Great. You are so helpful. One more thing, I need a taxi to arrive at the restaurant by the booking time Sentence13: Great! Thank you so much! Sentence14: What do you have in the way of guesthouses in the north? Sentence15: Well I can recommend the Acorn Guest House that is also rated 4 stars. Sentence16: There are 9 options that would suit those criteria, do you have any other things you need for your stay or would you like a recommendation? Sentence17: I have found 11 different guesthouses in the north. Were there any certain requirements you have in searching for a particular guesthouse? Sentence18: i have their info, what would you like to know? Sentence19: I can help with that. Where would you be departing from? Sentence20: Please provide a recommendation. Question: Who has spoken the sentence 15? (A) User (B) System
Answer:
Answer: (B) System