This solution provides a well-architected approach for a heterogeneous database migration from Oracle to a managed AWS service. It correctly identifies the use of the AWS Schema Conversion Tool (SCT) and AWS Database Migration Service (DMS) for this purpose. Amazon RDS for PostgreSQL supports the PostGIS extension, which provides native spatial data capabilities, meeting a key requirement. Most importantly, it addresses the need to query on-premises data as a foreign table by using AWS Direct Connect to establish a dedicated, private network connection, over which PostgreSQL's Foreign Data Wrappers (FDW) can securely connect to the on-premises Oracle database.

A. Amazon DynamoDB is a NoSQL database, which is an unsuitable target for a relational Oracle database without a major application rewrite. Amazon API Gateway does not provide foreign table support.
B. AWS Glue crawlers are used to discover data and populate the AWS Glue Data Catalog; they do not enable live foreign table queries from an RDS instance.
C. An internet gateway provides public internet access. It is not the appropriate or secure method for establishing a private, persistent connection to an on-premises database for foreign table queries.

1. AWS DMS and SCT for Oracle to PostgreSQL Migration: AWS Documentation, "AWS Schema Conversion Tool User Guide," section "Converting Oracle Schemas to PostgreSQL." This guide details using SCT to convert the source Oracle schema and code to a format compatible with PostgreSQL, and then using DMS to migrate the data.

2. Spatial Data Support in RDS for PostgreSQL: AWS Documentation, "Amazon RDS for PostgreSQL," section "Working with PostgreSQL extensions," subsection "PostGIS." This document confirms that the PostGIS extension is supported on RDS for PostgreSQL to "add support for geographic objects."

3. Hybrid Connectivity with Direct Connect: AWS Documentation, "AWS Direct Connect User Guide," section "What is AWS Direct Connect?." It states, "AWS Direct Connect creates a dedicated private connection between your data center...and AWS. This can reduce network costs, increase bandwidth throughput, and provide a more consistent network experience than internet-based connections." This is the required connectivity for stable foreign table access.

4. PostgreSQL Foreign Data Wrappers: The official PostgreSQL documentation (Version 14, Section 37.3, "Writing a Foreign Data Wrapper") describes the FDW feature. The oraclefdw extension allows a PostgreSQL database to connect to and query a remote Oracle database as if it were a local table, which directly fulfills the requirement. This connection would be established over the Direct Connect link.