Nouns are words that name people, things, places,
animals, etc.
When a noun ends with an 'o', we form the plural noun by adding an 'es' to it ('o' in 'tomato').
Option A: 'Tomatoes' is the plural form of the noun 'tomato'. Hence option A is correct.
Option B: 'Tomato' is a singular noun that names a fruit. It's not a plural noun and hence B is wrong.
Option C is wrong because 'B': 'tomato' is not a plural noun.
Option D is wrong because 'tomatos' is the incorrect spelling of the plural noun 'tomatoes'.