A user is comparing purchase options for an application that runs on Amazon EC2 and Amazon RDS. The application cannot sustain any interruption. The application experiences a predictable amount of usage, including some seasonal spikes that last only a few weeks at a time. It is not possible to modify the application.
Which purchase option meets these requirements MOST cost-effectively?

A. Review the AWS Marketplace and buy Partial Upfront Reserved Instances to cover the predicted and seasonal load.
B. Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run on Spot Instances.
C. Buy Reserved Instances for the predicted amount of usage throughout the year. Allow any seasonal usage to run at an On-Demand rate.
D. Buy Reserved Instances to cover all potential usage that results from the seasonal usage.