The air-born voice makes the speaker realize that he can be happy, as shown in option C.
The air-born voice, shown at the end of the poem, establishes that the speaker can be happy, as long as it promotes a change in attitude and a change in the way he sees himself, as he has all the necessary resources.
This question is about the poem "Self-Dependence" written by Matthew Arnold.
More information about poems in the link:
https://brainly.com/question/12207798