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
Q: customer: Hello. 
 agent: Hello, how can I help you today? 
 customer: Can you find me a direct flight to Washington? 
 agent: Sure, I am here to help you. 
 customer: Thank you. 
 agent: Kindly, share your selected airport codes. 
 customer: My source point is OAK and destination is IAD. 
 agent: May I know that when you have planned to travel? 
 customer: I will fly on Sept 08 and return on Sept 10. 
 agent: Do you prefer a connection limit? 
 customer: I prefer a direct flight. 
 agent: Is there any other concerns to say? 
 customer: No. 
 agent: On whose name, you want to reserve the ticket? 
 customer: My name is Virginia Phillips. 
 agent: Ok, please wait for a few minutes. 
 customer: Sure. 
 agent: Sorry to say that, no flights are found based on your given information. 
 customer: Ok, thank you for the information. 
 agent: Thank you for choosing us.
A:
no_flight