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

Example input: 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
Example output: Answer: (A) User
Example explanation: The sentence 1 is said by a user because the intent of it says that the information has to be gathered from the system
Q: Sentence1: I want a train going to london kings cross. Sentence2: I would like to travel on monday and leave after 15:30. Sentence3: Have a great trip. Sentence4: Thanks, that is all I need. Sentence5: Booking was successful.Reference number is : 1HLAC0TN . Sentence6: Yes I would like to book it for 2 nights from Saturday for 3 people please. Sentence7: Please book the 17:70 for 3 people. Sentence8: Yes please it needs to be for three people. Sentence9: Sorry about that. Worth House is a cheap guesthouse located in the north. Sentence10: I was able to book it, reference number is M9MIP9U1 Sentence11: There are four trains that depart every two hours. The earliest leaves at 17:70 and the last one leaves at 23:00. What's your preference? Sentence12: Great, thanks! Also, can you tell me about the Worth House, please? Sentence13: I didn't ask about a restaurant. I'm pretty sure that's a hotel. Sentence14: I am departing from cambridge. Sentence15: We have 70 trains that meet that criteria, what is your point of departure please? Sentence16: Great! What day would you like to leave? Do you have any preferred times to leave and arrive by? Sentence17: Actually, the earliest train, TR7786 leaves Cambridge at 17:00 and arrives at 17:51. Should I go ahead a book this for 3 people? Sentence18: i am not sure is that a restaurant? Question: Who has spoken the sentence 15? (A) User (B) System
A:
Answer: (B) System