Rapid elasticity is the most essential characteristic in this scenario, as it enables the enterprise to scale computing resources quickly and on-demand to handle large workloads during peak periods. This ensures that they can meet the increased demand without permanent investment in infrastructure. Metered utilization is a billing model but does not specifically address scalability. While high availability is important, it does not pertain to the scaling of resources. File synchronization is more related to data accessibility and availability across devices rather than scalability and integration with an on-premise data center.