The correct option is DoNotAllow.

DoNotAllow is not a valid Azure Policy mode. Policy modes determine how resources and types are evaluated during policy enforcement and the documented modes are All, Indexed, and Microsoft.KeyVault.Data. Since DoNotAllow is not one of the supported modes it is the correct choice for this question.

Microsoft.KeyVault.Data is an actual policy mode that targets Key Vault data plane operations and it is used when policies must evaluate secrets and keys at the data layer. That is why this option is not the correct answer to the question.

Indexed is a supported mode that evaluates resource properties that are indexed by the resource manager and it is commonly used for standard ARM resource policies. That makes this option a valid mode and therefore not the right answer here.

All is a supported mode that allows evaluation across a broader set of resource types including those that are not indexed. This option is valid as a mode so it is also not the correct choice for this question.

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