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

Sentence1: TR2634 leaves at 21:00 and arrives by 21:51. Would you like me to book that for you? Sentence2: Sorry, I'm actually not interested in a booking today, I just needed a train ID. I think that will be all! Sentence3: I need to go to London Kings Cross from Cambridge. Sentence4: I have booked Allenbell for yourself and two additional guests for five days. The reference number is N625QW6Q . Can I assist you with anything else? Sentence5: I have 10 trains leaving on that day. Do you have a time of arrival or departure please? Sentence6: I need to book for 3 people for 5 nights starting Wednesday. Can you give me a reference number? Sentence7: Yes, that will work. Thank you for your help! Sentence8: There are 10 cheap places that include free wifi. Is there a specific area you would like to stay in? Sentence9: Hi! I'm looking for a cheap place with free wifi. What are my options? Sentence10: How many people will be in your party on the train? Sentence11: Where will you be departing from and where will you be arriving? Sentence12: Thanks, I also need to find a train for Monday. Sentence13: I would like to leave after 19:00, other than that, I have no other preference. Please provide me with the train ID of one of these trains. Sentence14: I have 9 potential guesthouses for you to chose from. How about the Allenbell on the east side? Sentence15: Glad to help! Please enjoy your stay in Cambridge! Sentence16: No particular area, but I'd like it to be a guesthouse. Question: Who has spoken the sentence 6? (A) User (B) System
Answer: (A) User