Consider the following countries: I. Austria II. Bulgaria III. Croatia IV. Serbia V. Sweden VI. North Macedonia How many of the above are members of the North Atlantic Treaty Organization?

Among the listed countries, Bulgaria (2004), Croatia (2009), North Macedonia (2020), and Sweden (2024) are members of NATO. Austria maintains constitutional neutrality and is not a NATO member. Serbia is also not a NATO member and has historically been aligned differently due to the 1999 NATO bombing. Therefore, four of the six listed countries are NATO members.