Consider the following countries: 1. Albaina 2. Bosnia Herzegovina 3. Croatia 4. Macedonia Which of these countries has/have Adriatic Sea as a boundary?

Albania, Bosnia and Herzegovina and Croatia all have coastlines on the Adriatic Sea. Regional surveys and marine studies list the Adriatic as being shared by countries including Croatia, Bosnia and Herzegovina and Albania, among others, confirming that these three states border the sea [1]. Historical and boundary analyses of the Adriatic likewise treat Albania, Bosnia-Herzegovina and Croatia as Adriatic littoral states, with Croatia inheriting the largest portion of the former Yugoslav coastline and Bosnia-Herzegovina possessing a small but real Adriatic outlet at Neum [2]. By contrast, Macedonia (North Macedonia) is landlocked and has no Adriatic coastline. Therefore option 2 (1, 2 and 3) is correct.

Sources

1. [1] https://www.sciencedirect.com/science/article/abs/pii/S0025326X18308890
2. [2] https://www.durham.ac.uk/media/durham-university/research-/research-centres/ibru-centre-for-borders-research/maps-and-databases/publications-database/Maritime-Briefings-(Vol.-1-no.-8).pdf