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: There are 3 results for expensive british food in the centre area. The first is fitzbillies restaurant, would you like more information on it? Sentence2: I am looking for a train departing from Cambridge that would arrive by 19:45. Sentence3: Booking was successful, the total fee is 7.04 GBP payable at the station. Reference number is : 9YZO84HU . Can I help you with anything else? Sentence4: Unfortunately that is booked already. Would you like to book a different time? Sentence5: Certainly! I was able to book you for 2 people at Fitzbillies Restaurant at 13:15 on Sunday. Your Reference number is YHP8JIIA . Sentence6: That one sounds good, could you reserve me a table for 2 at 14:15? Sentence7: I am also looking for a very expensive restaurant located in the Centre. Do you have any suggestions? Sentence8: Thanks so much - that's all I need today. You've been a great help! Sentence9: Just to make sure I have this correct. Which day would you like the reservation booked for? Sentence10: The same day as the train, on sunday. Can I also get the reference number please? Sentence11: There are 33 expensive restaurants in the centre. Is there a particular kind of cuisine you're looking for? Sentence12: Train TR5389 leaves Cambridge at 17:50 and arrives in sly at 18:07. Can I book this for you? Sentence13: Thank you as well. Have a wonderful day. Sentence14: There are 1,029 trains that meet your needs. Would you like to narrow it down by destination, day, and/or the time it leaves? Sentence15: Yes, I'd prefer British food. Sentence16: Yes, I need a train that goes to Ely and leaves on Sunday. Sentence17: Can you try booking for 2 on Sunday at 13:15 instead? Sentence18: That works, can you book 2 seats for me please? Question: Who has spoken the sentence 16? (A) User (B) System
Answer: (A) User