You will be given a definition of a task first, then some input of the task.
In this task, you're given a dialogue between a customer and a flight booking agent with a gap in the conversation. Your job is to find the answer of the previous dialogue. Avoid using irrelevant extra information while creating the answer. The answer should be relevant to the question before the blank. If you fill the blank with a question, it should have an answer from the agent in the given dialogue. Fill the gap marked with underline.

customer: Hi. 
 agent: Hello. How can I assist you at this moment? 
 customer: Please make a reservation with the name of Nicole Martin from PHX. 
 agent: Sure, I will assist you with that. Can you please mention your preferable travel dates? 
 customer: I want to travel on Dec 20 and return back on Dec 22. 
 agent: May I know your destination airport code name? 
 __ 
 agent: May I know your connection limit for this trip? 
 customer: I need a single connecting flight. 
 agent: Do you have any another specifications? 
 customer: I prefer to travel in economy class. 
 agent: Is there any additional preferences do you have? 
 customer: No. 
 agent: Ok, please hold on a moment. 
 customer: Sure. 
 agent: AA flight available with connection limit 1 and fare is 100, shall I confirm this economy class flight? 
 customer: Yes, please confirm it. 
 agent: Your flight ticket is booked successfully, flight number is 1026. 
 customer: Thank you for the help. 
 agent: You are welcome Nicole Martin.
Output:
customer: Destination airport code is BOS.