问题：
[单选题] ______,businesses offer services for which they charge a fee that is based on the number of size of transactions they process.
A、In the fee-for-transaction revenue model
B、In the web catalog revenue model
C、In the traditional catalog-based retail revenue model
D、In the advertising-supported revenue model
参考答案：
A、In the fee-for-transaction revenue model
● 参考解析
