Step 1: Understanding the Concept:
This sentence completion question uses the words "Though" and "nonetheless" to establish a contrast between Edna St. Vincent Millay's personal life and her work ethic. We need to find a pair of words that are opposites.
Step 2: Detailed Explanation:
The second part of the sentence describes her as "producing several pages of complicated rhyme in a day." This indicates she was hardworking, productive, and methodical in her work. A good word to describe this is disciplined.
The structure "Though..., nonetheless..." requires the first word to be in contrast with "disciplined." We need a word that describes a characteristic that is the opposite of being disciplined.
Let's analyze the options with this in mind:
(A) "jaded" (tired, bored) and "feckless" (ineffective, worthless) are both negative and not clear opposites.
(B) "verbose" (wordy) and "ascetic" (self-disciplined, austere) are not direct opposites.
(C) "vain" (conceited) and "humble" are opposites, but "humble" doesn't fit the description of her being a productive writer.
(D) impulsive (acting without forethought) is a strong contrast to being disciplined (acting with control and routine). This pair fits the sentence's logic perfectly. An impulsive personal life contrasts sharply with a disciplined work life.
(E) "self-assured" (confident) and "sanguine" (optimistic) are similar in meaning, not contrasting.
Step 3: Final Answer:
The contrast between being "impulsive" in personal matters and "disciplined" in professional work is the most logical and fitting choice for the sentence. Therefore, option (D) is correct.