Which of the following contributes most directly to the author's theme of conflict?

a. the japanese-american reservoir crew and the armed government soldiers stand silently against opposite sides of the shack as they wait for clearance.

b. the shack has only one window and is very dark when the lights are
extinguished.

c. only a few japanese-americans were permitted to guard the reservoir.

d. each crew guards the reservoir for twenty-four hours, checking the chlorine shed, walking the perimeter and making sure the water continues to flow to the camp.