Which two loop-prevention mechanisms are implemented in BGP? (Choose two.)

[answerhappygod]

Which two loop-prevention mechanisms are implemented in BGP? (Choose two.)

A. A route with its own AS in the AS_PATH is dropped automatically if the route reenters its own AS.
B. A route with its own cluster ID in the CLUSTER_LIST is dropped automatically when the route reenters its own AS.
C. The command bgp allowas-in enables a route with its own AS_PATH to be dropped when it reenters its own AS.
D. The command bgp bestpath as-path ignore enables the strict checking of AS_PATH so that they drop routes with their own AS in the AS_PATH.
E. The command bgp bestpath med missing-as-worst assigns the smallest possible MED, which directly prevents a loop.