What element of plot is this passage an example of? A. Falling action
B. Exposition
C. Conclusion
D. Dénouement

Well, it's actually pretty simple. You see, the words hour and spring are often used with various meanings in the first place. 
The answer would be A, because 'hour' refers vaguely as time, and 'spring' in this case is not a body of water, but an action.