What does a BGP route reflector do when reflecting a route?

What does a BGP route reflector do when reflecting a route?

A.
It prepends its cluster identifier to the route’s cluster list.

B.
It prepends its own originator identifier to the route’s cluster list.

C.
It replaces the route’s cluster identifier with its own cluster identifier.

D.
It replaces the route’s originator identifier with its originator identifier.