I believe it is A because the others are run on sentences.
B. Royalty living in the "Old World"
Why?
Because Irish Immigrants, Native Americans, and African Americans were all mentioned as dreamers in "Let America be America Again" but Royalty living in the "Old World" was not mentioned to be a dreamer in the poem. Therefore, the answer is B. Royalty living in the "Old World".
I'm almost 100% sure its To Come, for it sounds the most like an infinitive verb.
