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.