Answer:
D) Numerator.
Step-by-step explanation:
When we say "subject area word", we mean any word that pertains to a particular field of study, subject or interest. It mainly refers to a particular field of knowledge that may be from the various fields of academics or anything.
Among the given words in the option, the word that is a subject-area word is "numerator" for it specifically is about mathematics. This word is used in mathematical calculations and pertains to this field of study most.
Thus, the correct answer is option D.