Her _____ nature made her an invaluable asset to the investigative team; she could effortlessly discern subtle inconsistencies and expose hidden truths.
Correct: C
'Perspicacious' means having a ready insight into and understanding of things. It describes someone capable of discerning inconsistencies. Garrulous means talkative, myopic means nearsighted (or lacking foresight), and obtuse means slow to understand.