What information does a router running a link-state protocol use to build and maintain its topological database？ （）

• A、 hello packets
• B、 SAP messages sent by other routers 
• C、 LSAs from other routers
• D、 beacons received on point-to-point links
• E、 routing tables received from other link-state routers
• F、 TTL packets from designated routers