Dependent territories are included
The island must be under complete control of the country, ex. Guinea is not the largest island of Papua New Guinea.
Cyprus has is considered to have complete control of the isle of Cyprus.
Australia is not considered an island
Singapore Island is not included
Fluvial Islands are accepted
Great idea for a quiz but there are some typos: it's Great Britain (-ain, nor Ian) and Hainan (not Nainan). Probably worth double checking for any others.