The correct option is A Girls, Class - Countable Nouns
Countable nouns refer to nouns that can be counted and they have a singular and plural form, like apple/apples. Uncountable nouns cannot be counted, and they don't have a plural form, like rice, flour, milk. From the given options, A is correct, as 'girls' and 'class' are countable, girls is the plural form of 'girl' and can be counted as four girls, as mentioned in the sentence. Class is a collective noun which can be counted as one class, two classes, and so on. Option B is incorrect because these words are not uncountable, they can be counted. Option C is incorrect because even though girls is countable, class is not an uncountable. It's a singular collective noun that can be counted as one class, two classes, and so on. Option D is incorrect because 'girls' is not an uncountable noun, it's a plural noun which can be counted, in the sentence itself it's mentioned "four girls" which gives the count of the number of girls: four.