Which VLAN value permits virtual machine guest tagging in vSphere 5 environment?

Which VLAN value permits virtual machine guest tagging in vSphere 5 environment?

A.
4095

B.
1

C.
4096

D.
0

Explanation:
http://vmnomad.blogspot.com/2011/07/vlan-tagging-and-use-cases-of-vlan-id.html

Page 12 and 13 from vsphere-esxi-vcenter-server-50-networking-guide.pdf