Meaning of город

In Russian language the word "деревня" is used for small villages without churches. Word "село" for normal villages with churches. And "поселок" for a settlement. Word "город" means town and city. In Russian statistics "город" is for over 10.000 citizens so you can use this word in your case

If your homework is an essay, I think you can use "городок." Example: Я живу в уютном городке Х. The word городок is more informal and literary. In more formal writing, you can use "город" with adjectives (example: небольшой город).

The primary difference between деревня/село and город is that город is an urban settlement, i.e. most of its residents are not involved in agriculture/hunting and so on.

Actually, this is not simply a matter of language. The thing is that every country has its own regulations on what should be considered a city, town, город, село, etc. As a Russian speaker, I can tell you that we struggle with the translation of English towns and cities in the same way. As for which one is the best, I believe you can say небольшой город, маленький город.