You need to ensure that Scope1 has a subnet mask of 255.255.255.0

Your network contains an Active Directory domain named contoso.com. The domain contains a
DHCP server named Server1that runs Windows Server 2012 R2.
You create a DHCP scope named Scope1. The scope has a start address of 192168.1.10, an end
address of 192.168.1.50, and a subnet mask of 255.255.255.192.
You need to ensure that Scope1 has a subnet mask of 255.255.255.0. What should you do first?

A.
From Windows PowerShell, run the Remove-DhcpServerv4PolicyIPRange cmdlet.

B.
From the DHCP console, modify the Scope Options of Scope1.

C.
From Windows PowerShell, run the Remove-DhcpServerv4Scope cmdlet.

D.
From Windows PowerShell, run the Set-DhcpServerv4Scope cmdlet.

Explanation:
Set-DhcpServerv4Scope
Sets the properties of an existing IPv4 scope on the Dynamic Host Configuration Protocol (DHCP)
server service.

Syntax:
Parameter Set: WithoutRange
Set-DhcpServerv4Scope [-ScopeId] <IPAddress> [-ActivatePolicies <Boolean> ] [-AsJob] [-CimSession
<CimSession[]> ] [-ComputerName <String> ] [-Delay <UInt16> ] [-Description <String> ] [-
LeaseDuration <TimeSpan> ] [-MaxBootpClients <UInt32> ] [-Name <String> ] [-NapEnable
<Boolean> ] [-NapProfile <String> ] [-PassThru] [-State <String> ] [-SuperscopeName <String> ] [-
ThrottleLimit <Int32> ] [-Type <String> ] [-Confirm] [-WhatIf] [ <CommonParameters>]
Parameter Set: WithRange
Set-DhcpServerv4Scope [-ScopeId] <IPAddress> -EndRange <IPAddress> -StartRange <IPAddress> [-
ActivatePolicies <Boolean> ] [-AsJob] [-CimSession <CimSession[]> ] [-ComputerName <String> ] [-
Delay <UInt16> ] [-Description <String> ] [-LeaseDuration <TimeSpan> ] [-MaxBootpClients <UInt32>
] [-Name <String> ] [-NapEnable <Boolean> ] [-NapProfile <String> ] [-PassThru] [-State <String> ] [-
SuperscopeName <String> ] [-ThrottleLimit <Int32> ] [-Type <String> ] [-Confirm] [-WhatIf] [
<CommonParameters>]