Q: You are shown a conversation between a user and system. Identify who has spoken the indicated sentence based on the conversation.
Sentence1: You would be on the train for an hour, is this OK? Sentence2: I'm sorry, the booking was unsuccessful. Would you like to try a different day or try booking another hotel? Sentence3: I'd like to arrive by 14:15. Sentence4: It looks like they run hourly at 32 minutes past the hour, starting at 5:32. Did you have a day and time in mind? Sentence5: Yes, I need a train to get me to Cambridge. I'm coming from Broxbourne. Sentence6: It doesn't really matter, I'm not familiar with the town. I just need free WiFi and free parking. Sentence7: How long will I be on the train? Sentence8: Oh, I'm sorry, that was my mistake. I do have you booked now for five nights now, reference number 1UX4GMPA . Is there anything else I can do for you? Sentence9: Can you try again, please? I never told you how many nights we need. We'd like to arrive Wednesday and stay for 5 nights. We're a party of 7. Sentence10: Thank you for contacting us. Have a great day. Sentence11: Sure, I can find one for you. What area of town would you like to stay in? Sentence12: No, thank you. The information was all I needed for today. Sentence13: The acorn guest house is located in the north and offers free parking and internet. Phone number is 01223353888 and has 4 stars. Sentence14: That's what I need. Will you book acorn guest house for me starting Wednesday for 7 people, please. Sentence15: TR3158 departs Broxbourne at 12:32, arrives at 13:32, and is a one hour ride. Would you like me to book it? Sentence16: Yes, so to clarify, what time will that train be departing? Sentence17: I'm looking for a guesthouse to stay in that's moderately priced. Sentence18: Sure, the train that arrives closest to 14:15 is TR7834 arriving at 13:32. How many people will be riding? Question: Who has spoken the sentence 17? (A) User (B) System
A:
Answer: (B) System