In AWS IAM, which of the following predefined policy condition keys checks how long ago (in
seconds) the MFA-validated security credentials making the request were issued using multifactor authentication (MFA)?

A.
aws:MultiFactorAuthAge

B.
aws:MultiFactorAuthLast

C.
aws:MFAAge

D.
aws:MultiFactorAuthPrevious

Explanation:
aws:MultiFactorAuthAge is one of the predefined keys provided by AWS that can be included
within a Condition element of an IAM policy. The key allows to check how long ago (in seconds)
the MFA-validated security credentials making the request were issued using Multi-Factor
Authentication (MFA).
http://docs.aws.amazon.com/IAM/latest/UserGuide/AccessPolicyLanguage_ElementDescriptions.
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