What do the images of grass in this excerpt from Whitman's "Song of Myself" symbolize?

"A child said What is the grass? fetching it to me with full hands;
How could I answer the child? I do not know what it is any more than he.
I guess it must be the flag of my disposition, out of hopeful green stuff woven.
Or I guess it is the handkerchief of the Lord,
A scented gift and remembrance designedly dropt,
Bearing the owner's name someway in the corners, that we may see and remark, and say Whose?
Or I guess the grass is itself a child, the produced babe of the vegetation."

A. The simplicity and innocence of childhood
B. The natural cycle of life and death
C. The interconnectedness of all living things
D. The transient nature of human existence