The aspect of the poem "The Red Wheelbarrow" by William Carlos Williams which most clearly marks it as a work of Modernism is that:
D. It uses very few words to communicate its message.
A group of writers at the beginning of the twentieth century rejected the traditional form of writing poetry about huge subjects. Rather they opted for simple and single subjects to write the poetry. They used very few words in order to convey the message of the poem. They wrote about the objects of everyday use and not about complex topics like love and beauty.
The most accurate answer to your question is D. It uses very few words to communicate its message :)
