The correct option is B A spirit undaunted by threatening dangers, a spirit that spurs one to action voluntarily and to pursue treks untrodden and inhospitable
The passage says that though the word 'adventure' embraces a company of other great words like courage, tenacity,
selflessness and faith; "its most potent ingredient cannot be expressed in one word." The author then goes on to describe this "potent ingredient" as the "spirit that urges men to volunteer to
undertake hazardous tasks" because "adventure implies the readiness and desire to embark on a course of action that entails risk." In this context, option A is the best answer.