After an ecommerce company moves its infrastructure to AWS, which cost remains the company’s direct responsibility?

The cost of application software licenses remains the company's direct responsibility because AWS operates under a shared responsibility model. While AWS manages the security of the cloud (including hardware, power, and physical security of data centers), customers are responsible for security in the cloud, which includes managing their own applications, data, and operating systems. This means the customer is accountable for licensing any third-party software they choose to run on AWS infrastructure. The other options (hardware infrastructure, power, and physical security) are all aspects of the underlying cloud infrastructure, which are managed and paid for by AWS.