Why does bierce use a flashback in section 2 of "an occurrence at owl creek bridge" instead of proceeding with the events taking place?

to introduce peyton farquhar
to emphasize the folly of romanticism
to depict the cunningness of the federal soldiers
to emphasize the naivety of the confederacy
to the reader know what led to the events in section 1
a.
1, 2, 3
b.
3, 4, 5
c.
1, 2, 5
d.
2, 3, 5
e.
1, 4, 5

To be honest i thinks its between the first answer and the third answer

In 911, a group of vikings lead by rollo besieged paris and chartres. after a victory near chartres on 26 august, charles decided to negotiate with rollo. the talks were led by hervé, the archbishop of reims. this resulted in the treaty of saint-clair-sur-epte, which granted rollo and his soldiers all the land between the river epte and the sea. it also granted him brittany, "for his livelihood". at the time, brittany was an independent land which france had not been able to conquer. in exchange, rollo promised the king his loyalty and military assistance when needed. also rollo also agreed to be baptised and to marry gisela, the king's daughter. the territory given rollo is about the same as upper normandy.

The answer will be yes