Which lines from the poem best shape the theme that joy can be found in experiencing the natural world?

This question is missing the options. I've found the complete question online. It is as follows:

Part A Which lines from the poem best shape the theme that joy can be found in experiencing the natural world?

A. "For oft when on my couch I lie / In vacant or in pensive mood,"

B. "They stretched in never-ending line / Along the margin of a bay:"

C. "Beside the Lake, beneath the trees, / Fluttering and dancing in the breeze."

D. "A Poet could not but be gay / In such a jocund company:"

Answer:

I believe the lines that best shape the theme that joy can be found in experiencing the natural world are:

D. "A Poet could not but be gay / In such a jocund company:"

Explanation:

The lines above belong to the poem "I Wandered Lonely as a Cloud", in which the author William Wordsworth narrates the memory of a day when he and his sister came across a field full of daffodils. The memory of such beauty still makes his heart fill with happiness, even when he is alone.

The theme of the poem concerns precisely that: how experiencing the natural world brings happiness. The daffodils dancing in the wind are a jocund (cheerful) company, and a poet could not but be gay - which means he can only feel happy when in the company of the dancing daffodils. Watching them dance, communing with nature, brings joy.