The correct option is A Countable Noun / Countable Noun
Countable nouns are nouns that can be counted as individuals, and they have a singular and plural form, like girl/girls, skateboard/skateboards. In the given sentence, the italicized words 'girls' and 'skateboards' both can be counted as individuals, hence option A is correct. Uncountable nouns are nouns that cannot be counted as individuals, they do not have a plural form, like rice, water, flour. Option B is incorrect because 'girls' is not an uncountable noun. Abstract nouns denote an idea, concept or any such non-physical entity, 'skateboards' does not refer to any concept, it's a physical object, hence it's not an abstract noun, option C is incorrect. Option D is incorrect because 'girls' is not an uncountable noun, it's the plural form of the noun 'girl'. 'Skateboards' is a countable noun as it can be counted, a common noun as it refers to a general thing, as well as a concrete noun that can be seen and touched.