Q: In this task, you are given a conversation between a flight agent and the customer. You are given 4 options and you need to select the goal of the conversation. It is provided as part of customer's context, which has to be one of the following: `book`: Make a new reservation, `cancel`: Cancel an existing reservation, `no_flight`: No flight found for the customer's preference, `no_reservation`: No reservation / No change / No cancellation was made in the conversation, mostly enquiring details
customer: Hello. 
 agent: Hello, how may I assist you today? 
 customer: William Wilson here. I want to travel from SFO to DEN for attending a business meeting. Can you please help me for booking the flight ticket? 
 agent: Sure, I will help you. 
 customer: Ok. 
 agent: May I know your dates of journey please? 
 customer: My departure date is 12/19 and return date is 12/21. 
 agent: Ok, please wait for a moment. 
 customer: Ok, I will wait. 
 agent: There is flight with the connections limit 0, are you ok with this ticket booking? 
 customer: Make sure my connections limit is 1. 
 agent: Sorry, there is no flight found as per your travelling details. 
 customer: Thank you for the information. 
 agent: You are welcome.
A:
no_flight