Nevertheless:
```
Starting with Junos OS Release 14.2R5 for MX Series routers and Junos OS Release 15.1X53-D63 for QFX10000 switches, you can explicitly configure an IPv4 or IPv6 MAC address for a default virtual gateway by using the virtual-gateway-v4-mac or virtual-gateway-v6-mac configuration statement at the [edit interfaces name irb unit logical-unit-number] hierarchy level. After you perform this configuration, the automatically generated virtual MAC is overridden by the configured virtual MAC. That is, when Layer 3 VXLAN gateway MX1 sends data packets, ARP replies, and neighbor advertisement packets, the configured virtual MAC is in the outer Ethernet header of these packets. As a result, interrmediary Layer 2 switch EX1 also learns the configured virtual MAC, thereby eliminating the possibility that the switch floods the domain with unknown-unicast packets.
```

A is correct.
```
When you configure a VGA for an IRB interface, the Layer 3 VXLAN gateway automatically generates IPv4 media access control (MAC) address 00:00:5E:00:01:01 or IPV6 MAC address 00:00:5E:00:02:01 for that particular virtual gateway. (This topic refers to the virtual gateway MAC address as a virtual MAC.) The automatically generated virtual MAC is not included as the source MAC address in packets generated by the Layer 3 VXLAN gateway. Instead, data packets and the source MAC address field in the outer Ethernet header of Address Resolution Protocol (ARP) replies and neighbor advertisement packets include the MAC address for the IRB interface. (This topic refers to the MAC address for the IRB interface as the IRB MAC.)
```