Travel Co Negotiates with Major Airlines to Obtain Access to Airline

Travel Co negotiates with major airlines to obtain access to airline tickets at reduced rates, and it sells the tickets to its customers through its website. Travel Co contracts with the airlines to buy a specific number of tickets at agreed rates and must pay for those tickets regardless of whether it is able to resell them. Customers visiting Travel Co's website search Travel Co's inventory of tickets, and Travel Co has latitude to set the prices for the tickets that it sells to its customers. Customers pay for airline tickets using credit cards, and Travel Co is the merchant of record. Credit card charges are pre-authorised; however, Travel Co incurs occasional losses as a result of disputed charges.
Travel Co is responsible for delivering the ticket to the customer. Travel Co will also assist the customer in resolving complaints with the service provided by the airlines. The airline is responsible for fulfilling all other obligations associated with the ticket, including the air travel and related services (that is, the flight) , and remedies for service dissatisfaction.
Travel Co should recognise revenue:

A) for the ticket price agreed with the airlines
B) for the fee charged to customers on a gross basis
C) for the fee charged to customers net of the amounts paid to the airlines
D) for the fee charged to customers net of credit card charges