Final answer:
The best word to fill in the blank is 'Agility,' as it specifically describes the swift and nimble movement of a fox when chasing prey, contrasting with hesitation which indicates reluctance.
Step-by-step explanation:
The phrase that best fills the blank in the sentence '“With _____________ , the fox sprang from its perch to chase its prey.’ would be 'Agility.' This is because when we consider the context of an animal, particularly a fox, chasing its prey, it would do so with quick, nimble movements that are necessary to effectively catch whatever it is pursuing. 'Grace' is also a possible answer; however, 'Agility' is more specific to the context of hunting and swift motion. 'Stealth' could be appropriate in terms of approach, but the act of springing is more about sudden movement rather than the secretive and quiet implications of stealth. 'Hesitation' is the least fitting option, as it conveys a sense of delay or uncertainty, which is contrary to the decisiveness expected in a predator's action when chasing prey. Given the quick and energetic nature of a fox's movements in hunting scenarios, as depicted in various passages with similar themes, agility is generally understood to best capture the essence of such actions.