An application is running on an Amazon EC2 instance. A SysOps Administrator is tasked with allowing the application access to an Amazon S3 bucket.
What should be done to ensure optimal security?

A. Apply an S3 bucket policy to allow access from all EC2 instances.
B. Create an IAM user and create a script to inject the credentials on boot.
C. Create and assign an IAM role for Amazon S3 access to the EC2 instance.
D. Embed an AWS credentials file for an IAM user inside the Amazon Machine Image (AMI).