and Taiwan are island nations.

Island nations are those that are surrounded entirely by water and may have more than one island comprising their nation.

There are 48 such nations in the world ranging from the famous ones like the UK and Japan to less known ones like Kiribati.

You included no options so the list of island nations in addition to Taiwan include;

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.