Answer:
The best option is indeed letter D. it is used to emphasize their great knowledge.
Explanation:
In Emily Dickinson's poem 'Will There Really Be a Morning?", the speaker is metaphorically questioning the existence of heaven. She wonders if Jesus, angels, and the peaceful place we conceive as heaven are truly real, if she will ever see them. She then directs her questions to the Scholar, the Sailor, and the Wise Man. The reason why she capitalizes those words is her regard of those people as possessors of great knowledge. She is turning to them for answers, trusting they may know what she doesn't:
Oh some Scholar! Oh some Sailor!
Oh some Wise Men from the skies!
Please to tell a little Pilgrim
Where the place called "Morning" lies!