Solution:
The task is to provide the plural form for the given singular nouns.
- FOOT: The plural of 'foot' is 'feet'.
- Country: The plural of 'country' is 'countries'.
- COUNTRIES: This is already a plural noun. The singular form is 'country'.
- people: This is already a plural noun. The singular form is 'person'.
Answer:
| Singular | Plural |
| FOOT | feet |
| Country | countries |
| Person | people |