Final answer:
To install a new child domain on Windows Server 2016, use the PowerShell cmdlet Install-ADDSDomain with the Credential parameter set to Get-Credential for the correct administrator permissions. The correct answer from the options provided is C: Credential (Get-Credential practicelabs\administrator).
Step-by-step explanation:
To install a new child domain in an existing Active Directory Domain network using Windows PowerShell on Windows Server 2016, the correct parameter to use for specifying credentials is Credential. The completed cmdlet with the correct option for credentials is:
Install-ADDSDomain -NewDomainName NORTHAMERICA -ParentDomainName PRACTICELABS.COM -InstallDNS -Credential (Get-Credential practicelabs\administrator)
Here, Credential specifies the credentials that have permission to perform the operation and Get-Credential cmdlet prompts you for those credentials. The correct answer from the options provided is C: Credential (Get-Credential practicelabs\administrator).