In stanza 5 of "Going for Water," a happy tone is developed when imagery is used to convey how the characters listen. The description of the characters as "gnomes" who pause "to listen ere we dared to look" creates a whimsical and playful atmosphere. The emphasis on their anticipation and joy in the moment contributes to an overall sense of happiness and excitement in the experience of seeking the brook. Therefore, the correct response is:
A happy tone is developed when imagery is used to convey how the characters listen.