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: I don't need to book, but could you tell me the total travel time, please? Sentence2: We don't have any moderately priced vegetarian places in town. Would you like to try a different type of food or a different price range? Sentence3: I have two - both in centre. The varsity Resturant and Bloomsbury. Would you like to book one? Sentence4: Please book for 6 people at 17:00 on Thursday. I'd also like the reference number. Sentence5: I'm also looking for a train. It should depart cambridge and go to stansted airport on thursday. Arrive by 17:00. Sentence6: Okay, what about international food? Sentence7: Unfortunately no, it has to be vegetarian, so i will have to make my own accommodations, thanks. Sentence8: No, I think that should be all for me today. Thank you so much, you've been very helpful! Sentence9: Your table was booked. Your reference number is MLK7FV6P . Sentence10: There are no vegetarian options in the area. Sentence11: I need to find a moderately priced vegetarian restaurant. Sentence12: You're welcome, have a great day! Sentence13: Would you be interested in TR9427? It arrives at 16:08 and departs at 15:40. Sentence14: That would be just fine. Sentence15: Sure thing. Travel time is 28 minutes. Can I help you with anything else? Sentence16: Make a reservation at Bloomsbury please, for Thursday night. Sentence17: How many tickets would you like to book? Sentence18: What time do you want to dine and how many people in your party? Question: Who has spoken the sentence 10? (A) User (B) System
Answer: (A) User