Which solution meets these requirements?
Use AWS Database Migration Service (AWS DMS) to migrate the database servers to Amazon RDS.
Use Amazon EC2 instances to migrate and operate the database servers.
Use AWS Database Migration Service (AWS DMS) to migrate the database servers to Amazon DynamoDB.
Use an AWS Snowball Edge Storage Optimized device to migrate the data from Oracle to Amazon Aurora.
Explanations:
AWS Database Migration Service (AWS DMS) is designed to migrate databases to Amazon RDS with minimal downtime and no need to modify the application code. This solution is ideal for migrating an Oracle database to a managed service such as Amazon RDS for Oracle.
Using Amazon EC2 instances requires manual management of the database, which increases operational overhead. This does not reduce overhead, and would require more effort than using a fully managed service like Amazon RDS.
Migrating from Oracle to Amazon DynamoDB is not appropriate, as DynamoDB is a NoSQL database and would require significant changes to the application, which the question specifies should be avoided.
AWS Snowball Edge is typically used for large-scale data transfers to AWS and is not intended for direct database migrations. Additionally, Amazon Aurora is a relational database, but moving from Oracle to Aurora would likely require changes to the database schema and code, making it unsuitable for this scenario.
I draft that the answer is:
Use AWS Database Migration Service (AWS DMS) to migrate the database servers to Amazon RDS.