The correct answers are B and C. Moving to the AWS Cloud can eliminate the costs associated with running and maintaining on-premises data centers, such as hardware procurement, maintenance, cooling, power, and facility costs, which is option B. Additionally, AWS operates at a massive scale, allowing them to achieve economies of scale that can lead to cost savings for customers, as they can leverage AWS's existing infrastructure and resources to achieve cost efficiency, which is option C. Option A is not correct because moving to the cloud typically involves trading capital expenses for variable operational expenses, not the other way around. Option D is incorrect because even when using cloud services, IT staff may still require training to effectively use and manage cloud resources. Option E is also incorrect because while AWS does offer the ability to reserve capacity, it is typically for terms of 1 to 3 years, not 7 years or more.