which vCloud Networking and Security feature would you utilize?

You have several vApps you need to deploy which process sensitive company information. In
order to protect the entire network where each of these vApps runs, which vCloud Networking and
Security feature would you utilize?

A.
NetFlow

B.
Firewall

C.
VLAN

D.
VXLAN

Explanation:
http://blogs.vmware.com/vsphere/2013/05/using-app-firewall-with-vxlan-networks.html