Consider the following countries:I.AustriaII.BulgariaIII.CroatiaIV.SerbiaV.SwedenVI.North MacedoniaHow many of the above are members of the North Atlantic Treaty Organization?

1. A

   Only three

   Only three. Four of the six names are NATO members.

2. B

   Only four

   Only four. Bulgaria, Croatia, Sweden and North Macedonia are in NATO. Austria and Serbia are not.

3. C

   Only five

   Only five. Austria or Serbia would have to be counted; they are not members.

4. D

   All the six

   All six. Austria is neutral; Serbia is not in NATO.

Summary. Official Set A key is (b) only four. Bulgaria, Croatia and North Macedonia are NATO members. Sweden joined in 2024. Austria is constitutionally neutral. Serbia is not in the Alliance. That is four of the six names.