what is the maximum size of associated storage capacity?

E, 6 TB

http://www.aiotestking.com/amazon/what-is-the-maximum-size-of-associated-storage-capacity/

The following table shows the IOPS and storage range for each database engine.

Range of Provisioned IOPS Range of Storage Range of IOPS to Storage (GB) Ratio
MySQL 1000 – 30,000 IOPS 100 GB – 6 TB 3:1 – 10:1
MariaDB 1000 – 30,000 IOPS 100 GB – 6 TB 3:1 – 10:1
PostgreSQL 1000 – 30,000 IOPS 100 GB – 6 TB 3:1 – 10:1
Oracle 1000 – 30,000 IOPS 100 GB – 6 TB 3:1 – 10:1
SQL Server Express and Web 1000 – 20,000 IOPS 100 GB – 4 TB 3:1 – 10:1
SQL Server Standard and Enterprise 1000 – 20,000 IOPS 200 GB – 4 TB 3:1 – 10:1