What it is: Retention is applied to an object version, controlling deletion/overwrite until a certain time.

What it’s for:

• Enforce “keep data until date X” per version (compliance).

Two valid exam facts (from the question):

• Different versions of the same object can have different retention modes and periods.
• If you apply retention explicitly to an object version, you specify a Retain Until Date for that object version.

Key idea: Retain Until Date

• A timestamp/date after which the object version can be modified/deleted (depending on permissions and mode).

Hard words:

• *object version* /ˈɑːbdʒekt ˈvɝːʒn/: phiên bản object
• *mode* /moʊd/: chế độ
• *timestamp* /ˈtaɪmstæmp/: mốc thời gian