The correct option is
A Hole
Nouns are naming words. For example: 'Ram is a boy.' Here, both 'Ram' and 'boy' are nouns. 'Ram' is a proper noun and 'boy' is a common noun. There are different types of nouns; i.e.; proper nouns, common nouns, material nouns, abstract nouns, concrete nouns, countable nouns, uncountable nouns, compound nouns and collective nouns.
NOTE: The given options are all common nouns.
Option B - A bird stays in a nest. Hence, option B is incorrect.
Option C - A beaver lives in a lodge. Hence, option C is incorrect.
Option D - A chicken lives in a coop. Hence, option D is incorrect.
Option A - An alligator lives in a hole. Hence, option A is the correct answer.
'A hole of an alligator.'