A developer deploys a custom application to three Amazon EC2 instances. The application processes messages from an Amazon Simple Queue Service (Amazon SQS) standard queue with default settings. When the developer runs a load test on the Amazon SQS queue, the developer discovers that the application processes many messages multiple times.
How can the developer ensure that the application processes each message exactly once?

A. Modify the SQS standard queue to an SQS FIFO queue.
B. Process the messages on one EC2 instance instead of three instances.
C. Create a new SQS FIFO queue. Point the application to the new queue.
D. Increase the DelaySeconds value on the current SQS queue.