Explanation
In this question, routes from EIGRP domain are redistributed into OSPF (with tag 111) then RIPv2 but without any filtering so R5 learns all routes from both EIGRP and OSPF domain. If we only want R5 to learn routes from OSPF domain then we must filter out routes with tag 111 and permit other routes.
The line "route-map O2R permit 20" is important to allow other routes because of the implicit deny all at the end of each route-map.