Line 23 signals a tone shift from reflective to happy.
This poem was written by Wordsworth, an English poet . He was a romantic poet from the XVIII ; he was interested in beauty more than in rhetoric or ornaments. Wordsworth's romantic sensibility replaced the classical form of some poets. In this poem he put the focus on the fact that " emotions are recollected in a state of tranquility." He used a reflective tone because he was thinking about the beautiful flowers , the daffodils, comfortably in a room. This memory filled his poet's mind and heart with pleasure and happiness.
These options are wrong:
-exhausted: The poet is not tired. He is just thinking about the beauty of nature seated in his couch.
-neutral: His tone is subjective . It is not objective. Nature touches his emotions.
-playful: He does not sound funny. He is serious but happy.