Answer:
D. enamored and disenchanted
Step-by-step explanation:
Let us first briefly define each of the forementioned pairs.
- slew means great number of something, excess
- superfluity denotes something unnecessary (either in number or in function)
From this we can see they pretty much mean the same thing, something that is unnecessarily large in number
- indulge means to take part in a desired, pleasuring activity
- partake means to participate or join in an activity (usually in eating and drinking, but it can refer to any other activity)
We see that these two words can have quite similar meaning, maybe not entirely synonymous, but definitely not an antonymous one.
- authentic is something real, genuine, with confirmed origin
- inexpensive is something that doesn't cost lot of money
These two words could be regarded as antonyms but only if certain contexts (if, for example, a found Rembrandt's picture is proved to be authentic, it would definitely cost a lot of money, if put for sale). However, they aren't always related in meaning.
- enamored means to be filled with love, affection and admiration for someone.
- disenchanted is a person disappointed with someone or something he/she previously believed in, admired, respected, cherished etc.
These two words could be regarded as true antonyms because they denote two opposing feelings.