What can explain the current state?

Refer to the exhibits.

Exhibit 1

Exhibit 2

Exhibit 1 shows a portion of the BGP routing table when the BGP solution was first deployed. Exhibit 2 shows the same portion at the current time.

What can explain the current state?
A . Due to changes in the private network, Switch-1 can no longer reach 192.168.2.1.
B . Switch-1 can no longer reach ISP 1 at 192.168.1.1.
C . Due to changes at ISP 1, Switch-1 now selects a different best route.
D . An administrator has applied a route map on Switch-1 that filters advertised routes.

Answer: C