Answer:
D. The word root.
Step-by-step explanation:
A root word can best be described as the words that hold the basic meaning which can be further modified by adding a suffix or prefix to form a new word. Yasmin decided to associate the meaning of "ruling" most likely by determining the word root i.e. 'cracy' meaning 'ruling' which can be employed to create certain other words like Bureaucracy, Democracy, Aristocracy, autocracy, etc. by adding distinct suffixes.