What is the minimum version of Windows supported to run VirtualCenter?

What is the minimum version of Windows supported to run VirtualCenter?

A.
Windows Server 2003 SP1

B.
Windows 2000 Server SP3 with .NET Framework

C.
Windows 2000 Server SP1

D.
Windows 2000 Server, SP4 with Update Rollup 1

E.
Windows Server 2003

Explanation:
ESX Server 3 Installation Guide ESX Server 3.5 and VirtualCenter 2.5, page 18.
VirtualCenter Server Software Requirements
The VirtualCenter Server is supported as a service on the 32?bit versions of these
operating systems:
Windows 2000 Server SP4 with Update Rollup 1
Windows XP Pro SP2
Windows 2003 Server SP1 (all releases except 64?bit)
Windows 2003 Server R2