In dbt, source freshness can be defined at the source level (affecting all tables) or overridden at the individual table level. When freshness is declared at the source root, dbt applies the freshness policy to every table within that source unless a specific table opts out. The official dbt documentation states that setting:
freshness: null
at the table level disables freshness checks for that specific table, even when the source itself defines default freshness rules. This is the only documented way to exclude an individual table from a source freshness policy.
Option B is incorrect because tables can override and disable freshness even when the parent source defines it. dbt's configuration hierarchy supports overriding child-level settings on a per-resource basis.
Option C (loaded_at_field: null) does not disable freshness-it simply removes the loaded_at_field, which would cause dbt to error because a freshness check requires a timestamp field to operate.
Option D (error_after: null) only removes the error threshold but does not disable freshness. The table would still participate in freshness checks and could trigger warnings.
Thus, the correct and dbt-supported method to exclude a table from freshness is to explicitly set:
freshness: null
making A the correct answer.