The pgdump utility is used for creating logical backups of a PostgreSQL database. It provides several output formats specified by the -F (or --format) option. The c value for this option selects the "custom" format (-Fc). This format is a compressed, archive-style backup that is not human-readable but is highly flexible. It is specifically designed to be used with the pgrestore utility, which allows for selective restoration of database objects and reordering of items during the restore process. The custom format is compressed by default, fulfilling the requirements of the question.

B. pgrestore: This utility is used to restore a database from an archive created by pgdump. It does not create backups.

C. pgbasebackup: This utility creates physical, binary backups of the entire database cluster file system. It does not produce the specific "custom format" archive associated with pgdump.

D. psql: This is the standard interactive terminal for PostgreSQL. It can execute SQL scripts, including plain-text dumps, but it is not a backup utility that creates compressed archives.

1. PostgreSQL 16 Documentation, pgdump: In the description of command-line options, the -F format or --format=format option is detailed. For the custom (c) format, it states: "Output a custom-format archive suitable for input into pgrestore. ... This format is also compressed by default."

Source: PostgreSQL Documentation, Server Administration, Backup and Restore, pgdump, Options section.

2. PostgreSQL 16 Documentation, pgrestore: The documentation's introductory paragraph clarifies its purpose: "pgrestore is a utility for restoring a PostgreSQL database from an archive created by pgdump in one of the non-plain-text formats (custom, directory, or tar)."

Source: PostgreSQL Documentation, Server Administration, Backup and Restore, pgrestore, Description section.

3. PostgreSQL 16 Documentation, pgbasebackup: The documentation describes its function for physical backups and its own compression methods: "pgbasebackup can make a base backup... The backup is made over a regular PostgreSQL connection... It can be created in either plain format... or as a tar archive." It mentions the -Z option for gzip compression, which is distinct from the pgdump custom format.

Source: PostgreSQL Documentation, Server Administration, Backup and Restore, pgbasebackup, Description section.