Answer: Permanent tables

According to Snowflake documentation and the community discussion, Fail-safe storage costs are incurred only for permanent tables. Fail-safe is a data protection feature that provides a 7-day period during which historical data is recoverable after Time Travel retention ends, but this applies only to permanent tables. External tables, data files in internal stages, and data files in external stages do not incur Fail-safe storage costs. The community discussion with 100% consensus on option B and reference to official Snowflake documentation confirms that permanent tables are the correct answer.

Author: LeetQuiz Editorial Team