What central idea is suggested in the poem “grass”?

click here to read the poem.

no matter where soldiers fall, they inevitably are forgotten over time.
when buried in foreign lands, soldiers are memorialized.
in places where wars were fought, trains now run.
by planting grass in battlefields, memories of war are softened.

Among the options given on the question the answer is option C.

By planting grass in battlefields,memories of war are softened.

Explanation: Grass is a three stanza poem by Carl Sandburg. Henry holt and company first published the poem in New York in 1918.

The central idea of the poem is to show how the battles and the aftermaths  get covered by the human. The poem describes the try of human as grass. The grass cover the battlefield means the memory and loss of war is covered by the human nature. They are not strongly memorized. People forget about their errors,like in the poem it is said as 'What is this,Where are we now?'. The damage of the battle of Waterloo and  Austerlitz is also covered by human to erase the error and memory of the war.

In the poem poet says,

Pile the bodies high at Austerlitz and Waterloo.  

Shovel them under and let me work—  

I am the grass; I cover all.

And pile them high at Gettysburg  

And pile them high at Ypres and Verdun.  

Shovel them under and let me work.  

Two years, ten years, and passengers ask the conductor:  

What place is this?  

Where are we now?  

I am the grass.  

Let me work.

So the grass is working as human to erase the war memories.