The so-called "Dark Romantics" notwithstanding, the best answer would be
C. Innocence
William Blake, although considered a "Pre-Romantic," wrote a book of poetry entitled, "Songs of Innocence and of Experience" -- in which he wrote
"Piping down the valleys wild Piping songs of pleasant glee
On a cloud I saw a child.
And he laughing said to me.
Pipe a song about a Lamb;
So I piped with merry chear,
Piper pipe that song again—
So I piped, he wept to hear.
...And I wrote my happy songs Every child may joy to hear"
This typifies Romanticism, in that the child, like the "Noble Savage"-indigenous peoples in pre-industrializing areas of the 18th- and-19th-centuries, remains in an effectively "unspoiled" state of being.