Uncertain whether his (i) ________ attire could impress the suave, nattily-dressed executive—despite her frequent affirmations of a fondness for rural life—Francis reduced himself to near (ii)_______ through new wardrobe acquisitions. If only he had known that the executive was secretly ashamed of her (iii) ________ showboating, which she only indulged to conceal her financial ruin.

Since the executive had a fondness for rural life, his attire which was meant to impress the executive too would have been rustic. Since natty means smart an fashionable we can eliminate it; along with exclusive. Therefore, georgic - which means rustic or pastoral - is the correct answer.

Francis could not have reduced himself to near lethargy or malaise through his new wardrobe acquisitions, as it does not make sense to suggest thus. But yes, he could reduce himself to near penury - or poverty - through such new wardrobe acquisitions. The phrase "if only" which suggests that he was ignorant of her "financial ruin" also indirectly suggests his folly in driving himself to penury.

Since she was nattily dressed to conceal her financial ruin, it has to be sartorial showboating and not runic (magic ancient letters) or bombastic (high-sounding and inflated). Bombastic almost conveys the same sense as showboating, so can be discarded, and also it is not as precise as sartorial in this context.