why does Whitman use the words "rising and gliding" to describe the speaker's exit from the classroom ?

We would say the answer would be C. These words suggest that the speaker is happy to leave.
Answer:
Whitman uses the words to create a feeling of boredom.
Explanation:
When you read the poem, you can notice the nostalgic and boredom feelings presents in the lecture;the speaker is trying to express this feeling with his words. The previous sentence, relates to similar feelings like being sick and tired, which support the answer.