What are three valid objects to place in a vApp?

What are three valid objects to place in a vApp? (Choose three.)

A.
Folders

B.
Hosts

C.
Resource pools

D.
vApps

E.
Virtual machines

Explanation:

http://pubs.vmware.com/vsphere-50/index.jsp?topic=/com.vmware.vsphere.vcenterhost.doc_50/GUID-3B5AF2B1-C534-4426-B97A-D14019A8010F.html