For which of the following use cases are Simple Workflow Service (SWF) and Amazon EC2 an appropriate solution?

A. Using as an endpoint to collect thousands of data points per hour from a distributed fleet of sensors
B. Managing a multi-step and multi-decision checkout process of an e-commerce website
C. Orchestrating the execution of distributed and auditable business processes
D. Using as an SNS (Simple Notification Service) endpoint to trigger execution of video transcoding jobs
E. Using as a distributed session store for your web application

Answer:
B. Managing a multi-step and multi-decision checkout process of an e-commerce website
C. Orchestrating the execution of distributed and auditable business processes