The pgrestore utility is designed to restore PostgreSQL databases from archives created by pgdump in non-plain-text formats. The custom (-Fc) and tar (-Ft) options both generate such archive files. The custom format is compressed and flexible, while the tar format is an uncompressed archive. Both are explicitly designed to be used as input for pgrestore, which allows for selective restoration and reordering of archived items. The plain text format (-Fp) creates a SQL script that must be restored using a client like psql.

A. -Fp (plain text format): This option creates a plain SQL script file. This type of backup is restored by piping the script into the psql client, not by using pgrestore.

B. -Fc (custom format): This option is correct, but it is not the only correct option listed. Therefore, it is an incomplete answer.

C. -Ft (tar format): This option is also correct, but like option B, it is not the only correct option listed, making it an incomplete answer.

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1. PostgreSQL 16 Documentation, pgdump: In the description of the -F or --format option, it specifies the output formats. It states that custom (-Fc) and tar (-Ft) formats are "suitable for input into pgrestore." In contrast, the plain (-Fp) format is described as a "plain-text SQL script file."

Source: PostgreSQL Documentation, Server Administration > Backup and Restore > pgdump. Section: "Options".

2. PostgreSQL 16 Documentation, pgrestore: The very first sentence in the description of the pgrestore utility 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." This explicitly excludes the plain format and includes the archive formats.

Source: PostgreSQL Documentation, Server Administration > Backup and Restore > pgrestore. Section: "Description".

3. PostgreSQL 16 Documentation, Chapter 26. Backup and Restore: This chapter provides a general overview. Section 26.1, "SQL Dump," explains: "The output of pgdump can be restored using the psql program... pgdump can also produce output in other formats that are intended to be used with pgrestore... pgrestore can handle the archive files."

Source: PostgreSQL Documentation, Server Administration > Chapter 26. Backup and Restore. Section: 26.1. "SQL Dump".