Final answer:
The command to enable MFA for a user account in PowerShell is not provided among the options, and typically involves using the Azure AD module for PowerShell with a set of cmdlets, possibly including 'Set-MsolUser' for Azure AD environments.
Step-by-step explanation:
To enable Multi-Factor Authentication (MFA) for a user account in PowerShell, the correct command is not specified in the options provided. For Azure Active Directory (Azure AD), the process typically involves using the Azure AD module for PowerShell. The syntax for these commands can change over time, and it's important to refer to the latest documentation for Azure AD or the specific environment you are managing.
However, as of my last update, a command like Set-MsolUser might be used to configure properties for a user, including enabling MFA, but this would typically be part of a more complex script or set of commands that use the Azure AD module's cmdlets to enforce MFA requirements.