Which reason explains this behavior?

A customer is running a guest WLAN with a foreign/export-anchor setup. There is one anchor WLC in the US and two in Europe. Anchor WLC priorities are used to prefer local anchors. During a routine network audit, it is discovered that a large number of guest client sessions in the US are anchored to the WLCs in Europe .

Which reason explains this behavior?
A . The foreign WLC failed and recovered.
B . The US anchor WLC failed and recovered.
C . The US anchor WLC is anchored to itself with a priority value of zero.
D . The anchor WLC is in the same mobility group.

Answer: B

Explanation: https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-1/Enterprise-Mobility-8-1-Design-Guide/Enterprise_Mobility_8-1_Deployment_Guide/WirelessNetwork_GuestAccessService.html