The correct answer is B, Amazon Aurora PostgreSQL. Amazon Aurora is a fully managed relational database service that is compatible with both MySQL and PostgreSQL. It is designed to provide high performance and scalability while being fully compatible with existing PostgreSQL applications and tools, meaning no changes are required to the queries. This makes it an ideal choice for migrating a standard PostgreSQL database to the AWS Cloud without altering the queries and with the goal of maximizing query performance. Amazon RDS for PostgreSQL, while also a fully managed service, may not offer the same level of performance as Aurora for this specific use case.