You are evaluating a Windows Azure application. The application uses one instance of a web role. The role instance size is set to Medium. The application does not use SQL Azure.   You have the following requirements for scaling the application：   - Maximize throughput.  - Minimize downtime while scaling. - Increase system resources.   You need to recommend an approach for scaling the application.  What should you recommend？（）  

• A、 Set up vertical partitioning.
• B、 Set up horizontal partitioning.
• C、 Increase the number of role instances.
• D、 Change the role instance size to large.