A Company Has Multiple Applications That Use Amazon RDS for MySQL

A company has multiple applications that use Amazon RDS for MySQL as is database. The company recently discovered that a new custom reporting application has increased the number of Queries on the database. This is slowing down performance. How should a solutions architect resolve this issue with the LEAST amount of application changes?

A) Add a secondary DB instance using Multi-AZ.
B) Set up a road replica and Multi-AZ on Amazon RDS.
C) Set up a standby replica and Multi-AZ on Amazon RDS.
D) Use caching on Amazon RDS to improve the overall performance.