Note: Cells in parentheses e.g. (C5) indicate references to the clues in those cells.
Based on this first hint, we know that C1 has a country that has more people than India. The only country more populous than India is China, so China goes in C1.
Directly from the clue, we input Suriname into F4. The Bahrain hint won’t be covered in this tutorial, but if you took different steps than the ones in this tutorial then it could be relevant.
Since every row represents a continent (F4), Row 4 represents South America (since Suriname is in South America). Column C contains the most populous country on its continent (A1), so C4 is Brazil (the most populous country in South America).
Directly from the clue, put Morocco in A2 and Iceland in B3.
Morocco is in Row 2, so Row 2 represents Africa. The most populous country in Africa is Nigeria, so C2 contains Nigeria. Similarly, Europe is represented by Row 3 (B3). Russia goes in C3 as the most populous nation from Europe.
As a North American country, Canada MUST go in Row 5 because it is adjacent to Brazil (A2), and is neither European nor South American. While we don’t know where Canada goes, we DO know that since the USA is the most populous country in North America, the USA must go in C5.
B4 must be the only box in Column B that does not contain an island (C5), because South America is the only continent to contain no island nations. Thus B5 must be an island nation. Canada must go in either B5 or D5 (A2), but since it is not an island, it MUST go in D5 (C5).
There are only two 4-letter countries from the Americas: Cuba and Peru are both in the puzzle (B3). So Cuba must be in Row 5 somewhere. Cuba is also the only island nation in Row 5 (D5), and so it must go in B5, the “island column.” (C5)
There are three “United ___” countries: United States of America (North America), United Arab Emirates (Asia), and United Kingdom (Europe). Since we already have USA, we know UAE goes in D1 and UK goes in D3 (C3).
There is only one 1-syllable country starting with S: Spain (B5). So Spain goes in Row 3. Since Spain cannot be adjacent to Suriname, the only place that Spain can go is A3.
South American countries in alphabetical order (A3): Argentina – Bolivia – Brazil – Chile – Colombia – Ecuador – Guyana – Paraguay – Peru – Suriname – Uruguay – Venezuela. Brazil is 3rd in Row 4, which means Argentina and Bolivia must appear in A4 and B4. We also know that Peru is in the quiz (B3). Since there are no countries alphabetically between Peru and Suriname, Peru goes in E4.
The only “O” country in the world is Oman (A4), which appears in Asia (which is Row 1). Therefore Oman goes in F1.
Consider hint D3. Column A has Argentina. Column B has Bolivia. Column C has China. Column D does not yet have any country. There are no D countries from South America, and only 2 D countries in Africa: Djibouti and Democratic Republic of the Congo. The latter cannot be in the quiz (F1), so Djibouti must go in D2.
There are only three North American countries whose capitals end with “City” (D1): Guatemala, Mexico, Panama. Therefore, Guatemala is in the quiz, which implies that Madagascar is also (B4).
The three African 4-letter countries are Mali, Chad, and Togo. Since Morocco and Madagascar are in the quiz and only 2 African countries starting with M are in the quiz (C2), Mali is not. Therefore Chad and Togo are in the quiz.
Madagascar must go in B2 because it is the only island of the remaining African nations: Madagascar, Chad, and Togo (C5).
Column E must have an E country. There are no E countries in Asia (remember East Timor is called Timor-Leste); the only African countries remaining are Chad and Togo (E4 & C2); and the only North American countries remaining are Guatemala, Mexico, and Panama (D1). Therefore the E country goes in E3. The only E country in Europe is Estonia, so Estonia goes in E3.
The only F countries are Fiji, Finland, and France. There is no Oceania row, so the F country must be in Europe. However, we know Finland is not in this quiz (D2) because El Salvador is not (D1). Therefore, France goes in F3.
The most southern-reaching country in the world is Chile (F3). Chile goes in D4.
Kyrgyzstan is in the quiz (D4), and in Row 1 because it is Asian. Since it is not an island, it cannot go in B1 (C5), therefore Kyrgyzstan is in E1. Mexico must then be in A5 (D4).
The 2 remaining North American countries are Guatemala (4 syllables) and Panama (3 syllables). Therefore Panama goes in F5 (E3), and Guatemala must go in E5.
Togo must go in F2 (B2), so Chad must be in E2.
The only 2-word country in the quiz so far is United Kingdom, so the final nation must be two words in length (E1), Asian (F4), and an island (C5). The only nation fitting this criteria is Sri Lanka, so Sri Lanka completes the puzzle.