Question

What does grass likely symbolize in these lines from the poem? 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.
(from "A child said, What is the grass" by Walt Whitman)
A.) undying curiosity
B.) helplessness
C.) an optimistic spirit
D.) precociousness