PostgreSQL provides the information schema and system catalogs as means to retrieve information about objects within a database.
The information schema is implemented as views stored in a schema named 'information_schema'. Its specifications are defined by the SQL standard, hence the names of views and columns, as well as the information they provide, are common across many RDBMSs. Therefore, SQL scripts that retrieve information from the information schema are likely to be usable as-is in other RDBMSs. However, not all RDBMSs support information schemas (for example, Oracle does not provide one), and information about PostgreSQL's proprietary extensions is not included in the information schema.
System catalogs are implemented as tables or views that have names starting with 'pg_'. As the name suggests, they are not compatible with other RDBMSs, but they do include information about PostgreSQL's proprietary extensions.
Information about tables and columns is stored in 'tables' and 'columns' in the information schema, and in 'pg_tables' and 'pg_attribute' in the system catalogs, respectively. Using SELECT statements, users can retrieve information within the scope of their privileges. Connect to the database with psql and check what columns are available by executing '\d information_schema.tables' or '\d pg_tables', and also try executing SELECT statements.

This is a question where you need to select the incorrect option, so the correct answer is D.