The forgotten spot where Henry encountered ____ corpses was not a place where he would longingly look into their eyes as he did with the other dead ____ soldier.

The best answer is C) five, Union (even though the text does say "four or five"). This is because the dead man from before was a Union soldier. Regardless, here's the reference:

"Farther off there was a group of four or five corpses keeping mournful company. A hot sun had blazed upon this spot. . . . In this place the youth felt that he was an invader. This forgotten part of the battle ground was owned by the dead men, and he hurried, in the vague apprehension that one of the swollen forms would rise and tell him to begone."