Question on Implementation with .net Business connetor and EP, a Help Server and a Synchronization proxy in ax 2012

You need to plan the server hardware and software required for the Microsoft Dynamics AX 2012 implementation. Your planned implementation will include a .NET Business Connector, an Enterprise Portal, a Help Server and a Synchronization proxy. Which components must run on a 64-bit operating system?

Answer.
 
Enterprise Portal.
Help Server.
Synchronization proxy.