The correct answer is A, as it highlights the key advantage of cloud computing's elasticity and scalability. With AWS, users can dynamically launch and terminate compute instances in response to actual demand and workload requirements, which allows for more efficient resource utilization and cost optimization. This flexibility is a significant benefit over traditional on-premises data centers where provisioning resources often requires more manual work and time. Options B, C, and D do not capture the unique benefits of cloud computing as effectively as option A does.