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

Sentence1: Yippee Noodle Bar meets your criteria, would you like their information? Sentence2: Thank you for using the Help Desk. Have a great day! Sentence3: I should leave Cambridge on sunday and arrive in london liverpool street by 14:30. I need 4 tickets and a reference number. Sentence4: Yeah, tell me the address for that restaurant and the type of food they serve Sentence5: Booking was successful, the total fee is 66.4 GBP payable at the station . Reference number is : B8QZ32WO. Can I help with anything else? Sentence6: Yes, that's perfect. I need tickets for 4 people, please. Sentence7: Yes, i need to find a restaurant to visit in the centre of town. Preferably in the moderate price range. Sentence8: TR5504 would arrive at 13:27, would that work? Sentence9: Do you know what time you need to depart or arrive by so I can narrow the options? Sentence10: I will be traveling on a Sunday, and I need to arrive by 14:30 Sentence11: You will be traveling on Thursday or Sunday? You've said both. Sentence12: There are 21 that fits your criteria. Which cuisine would you like, to help narrow your choices down? Sentence13: They are an Asian/Oriental restaurant, and are located at 40428 King Street City Centre. Is there anything else I can assist you with? Sentence14: It doesn't matter. Sentence15: That is all that I need. Sentence16: I need a train from cambridge to go to london liverpool street Sentence17: sure, what day are you traveling? Sentence18: I will be traveling on Thursday. Question: Who has spoken the sentence 16? (A) User (B) System
Answer: (A) User