Studying for the AWS CSA Associate level exam. Choosing the right DB option seems to be one of my weak points. Im having trouble identifying best use case scenarios for each DB option (RDS, Redshift, Dynamo). Anyone have any good way to remember?

RDS -> Standard Relational Database (MySQL, Aurora, Oracle, PostgreSQL)
Redshift -> OLAP -> For Analytics processing, petabyte size data, complex queries running here
DynamoDB -> high scalable No-SQL. Key-value oriented. e.g. store data from IoT devices, data from customer usage in an app