Answer:
A. Species
Step-by-step explanation:
Species is the most specific level of classification in taxonomy.
One mnemonic that can be used to remember the order of ranks is:
Dear King Philip Came Over For Good Soup
This stands for domain, kingdom, phylum, class, order, family, genus, species.
And, this is in order of the most broad to the most specific rank.
So, A is the correct answer.