The correct answer is C, Amazon Redshift. Amazon Redshift is a fully-managed, cloud-based data warehousing service designed for handling large-scale, complex analytical queries. It is optimized for querying and analyzing structured and semi-structured data using SQL. This makes it an excellent choice for companies that need to perform complex analytical queries. Amazon RDS (A) is a relational database service, Amazon DynamoDB (B) is a NoSQL database service, and Amazon ElastiCache (D) is an in-memory data store, none of which are primarily designed for complex analytical queries like Amazon Redshift.