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: Thank you. Goodbye. Sentence2: I also need to find a train from ely to cambridge. Sentence3: Is the travellers rest restaurant still open? Sentence4: I will be traveling on Sunday. Sentence5: lad we could help, call back soon! Sentence6: I'd like to arrive by 08:15. Please select the first option that comes up and book for 6 people, then send me the reference number Sentence7: Alright I have 10 trains. Please tell me when you want to leave or arrive Sentence8: Thank you for using our services. Have a great day! Sentence9: The booking was successful and your reference number is CKRJK7NI . Sentence10: Let me narrow down the choices. What day will you be traveling? And, what time do you want to arrive or depart? Sentence11: Can I book a table for six people on Sunday? At 12:15? Sentence12: It appears that they are open, but their number is 01223276182 to verify. Does that help? Sentence13: That is all I needed, thank you! Sentence14: Reference number is : 7WXPZ42X . Anything else? Question: Who has spoken the sentence 13? (A) User (B) System
Answer: (B) System