Free-Verse poem contributes to the theme of the poem as:
Option C: The absence of rhyme and meter brings out the meaningless nature of war that destroys lives and causes grief to innocent people.
Explanation:
The mentioned poem by 'Stephen Crane' highlights the brutality of war. It portrays the pain of separation by the the loved ones of the soldiers who die in the war.
He doesn't focus on the heroism of the soldiers instead talks about the psychological suffering of the people because of war.
Free verse poem is the one which doesn't have a specific rhyme and meter. It can have breaks in the stanzas. Absence of rhyme and meter highlight how meaningless a war which only destroys lives and brings sadness all over. Thus, free verse poem contributes to the theme of the poem.