Local Preference Comparison: Local preference is the first criterion BGP uses to select the best path. The higher the local preference, the more preferred the route. Here, the first route has a local preference of 150, while the other two routes have a local preference of 100.

Best Path Selection: Since the first route has the highest local preference (150), it will be preferred over the other two routes regardless of the AS Path length or any other attributes.

RIB-Out: The RIB-Out (Routing Information Base - Outbound) contains the routes selected for advertisement to peers. As only the best path is advertised, only the first route with the highest local preference will be included in the RIB-Out.

References:

Nokia Border Gateway Protocol Fundamentals

RFC 4271 - A Border Gateway Protocol 4 (BGP-4)