Answer:
Line 19 signals a tone shift from joyful to reflective.
Wordsworth (XIX) worships nature and thinks it is a source of inspiration for a poet. When he is outside, he can appreciate the beauty of nature. In this poem he describes enthusiastically the daffodils. This gives him energy and happiness -bliss- when he gets back home and finds himself alone. The beautiful images of the flowers will come to his mind and will fill his heart with pleasure. He compares his heart beats with the movement the daffodils made in the wind: "And then my heart with pleasure fills,//And dances with the daffodils."
These options are not right.
-concerned . ( The poet is not worried about anything in particular).
-curious. ( He feels curious and amazed. Nature attracts the poet's attention. Anyway, this can be his tone before line 19).
-suspicious. ( Wordsworth does not feel suspicious about nature but attracted towards it).
Explanation:
