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

Sentence1: I apologize for the extended wait. Your seats have been reserved. Your reference # is LR5KLQWT . Is there anything else I can assist you with? Sentence2: You're welcome! Please contact us if you need additional assistance during your visit to Cambridge! Sentence3: That sounds great! Thanks for all your help; that's all I needed today. Goodbye! Sentence4: Did you complete the booking? I need the reference number. Sentence5: I sure can! What day and times are you looking for? Sentence6: Great I'm also looking for a park to visit in the centre of town. Sentence7: I'll be coming in from Norwich on Friday. I'll need to leave after 11:30, please. Sentence8: Can you help me find a train to Cambridge? Sentence9: Yes, I'd be more than happy to book TR9900 for 5 people. Would you like a reference number? Sentence10: Yes please give me the reference number Sentence11: How about TR9900 that leaves at 05:16? Sentence12: Okay. The only park in the centre is cambridge university botanic gardens. Their address is bateman street, postcode is cb21jf, phone number is 01223336265, and the entrance fee is 4 pounds. Sentence13: Give me one moment to complete the booking. Sentence14: That sounds just like what I needed. Can you please make a booking for 5 people? Question: Who has spoken the sentence 1? (A) User (B) System
Answer: (B) System