The correct option is A soil, fertility - Uncountable
Countable nouns refer to things that can be counted, they have a singular and plural form, like apple/apples. Uncountable nouns refer to things that cannot be counted, and do not have a plural form, like rice, milk, flour. In the given sentence, 'soil' is made up of a million particles which cannot be individually counted, it's referred to as an entire mass, hence it's an uncountable noun. 'Fertility' is a state of being fertile, it's an abstract noun that cannot be counted, it's an uncountable noun, hence Option A is correct. Option B is incorrect because it states that both these nouns are countable, which isn't true. You cannot count soil, which is next to impossible to count, as it is made up of minuscule particles, and fertility is an abstract noun that describes a state of being. Option C is incorrect because 'black' is an adjective that modifies the noun 'soil', it is not an uncountable noun. Option D is incorrect because 'soil' and 'fertility' cannot be counted, and 'black' is not a noun.