What can the administrator do immediately to resolve the issue and prevent a future outage?

Scenario: A Citrix Administrator found that whenever a NetScaler VPX high availability (HA) pair of appliances fails over, the load-balanced websites are NOT accessible. The administrator investigated the issue and found that the router and switches do NOT support gratuitous ARP (GARP).

However, the administrator cannot immediately afford to upgrade the network infrastructure.

What can the administrator do immediately to resolve the issue and prevent a future outage?
A . Migrate the VPX pair to different hypervisor hosts.
B . Replace the NetScaler VPX appliances with NetScaler MPX appliances
C . Configure a Virtual MAC (VMAC) on the NetScaler.
D . Utilize IPv6 instead of IPv4.

Answer: D