Several files were stored, but only the damaged files were restored. Choose the sentence that preserves that meaning.
The files, which were damaged, were restored.
The files which were damaged were restored.✓Respuesta correcta
The files which were damaged, were restored.
The files, that were damaged were restored.
Explicación
Without commas, which were damaged selects the particular files that were restored. The comma-set version is tempting, but it treats the damage as extra information about all the already-identified files.