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 can I aid you? 
 customer: Please help me in booking flight ticket from CLT to DFW. 
 agent: Sure, I am happy to help you. Please let me know your travelling dates. 
 customer: My trip dates are Apr 18 to 20. 
 agent: Do you prefer any lay by in between journey? 
 customer: I need a connecting flight. 
 agent: Is there any class preference for you? 
 customer: I need to travel in business class. 
 agent: May I know your good name please? 
 customer: Myself Michelle Lopez. 
 agent: Do you have any other specifications? 
 customer: No. 
 agent: Thanks for providing details, we are unable to provide flights on your journey routes. 
 customer: Ok, no problem. Thank you. 
 agent: Thank you for choosing us.
A:
no_flight