Suppose Marlene Has Purchased a Non-Refundable $700 Plane Ticket

Suppose Marlene has purchased a non-refundable $700 plane ticket.But, at the last moment, she cannot take the trip.She can, however, sell the ticket.The cost of sending the ticket to a buyer through overnight mail is $20, and it costs $10 for a courier to get the ticket to the post office for overnight delivery.What is the minimum amount of money Marlene should accept for the ticket?  

A)  $730, because that is the total cost of the ticket and getting it to the buyer 
B)  $720, because that is the total cost of the ticket and of getting it to the buyer 
C)  $700, because that is what the ticket cost 
D)  $30, because the ticket cost is a sunk cost