Answer:
Option B, realism
Explanation:
Ambrose Bierce was considered as a realist author. He wrote about realtic events or happenings.
In his marvelous work "An Occurrence at Owl Creek Bridge" , he in depth explained the troop formation and military arrangement structure and also criticized the nation/regions involved in civil war. Since realism could be seen in his work & ideology, he supported realism movement which was launched to oppose the literary movement of romanticism. Bierce being a cynical person since childhood believed in living a purposeful live in synchronization with natural environment.
Thus, option B seems to be the correct answer
