RODC Option Greyed Out In DCPROMO In Windows 2008

Read Only Domain Controller (RODC) is a new server that has been introduced in Windows 2008. RODC as the name suggest, does not have a writable copy of active directory. It only hot a readable copy of the active directory (Just like secondary zones)

Now, the basic prerequisites of having a RODC Server in the domain is that we need to have a writable Windows 2008 domain controller. We cannot have RODC as the first Windows 2008 Server

Hence, while running the DCPROMO Wizard for the very first time on a Windows 2008 Server, the RODC option is greyed out... Simple...