Read the excerpt from "A Quilt of a Country."

Once these disparate parts were held together by a common enemy, by the fault lines of world wars and the electrified fence of communism. With the end of the cold war there was the creeping concern that without a focus for hatred and distrust, a sense of national identity would evaporate, that the left side of the hyphen—African-American, Mexican-American, Irish-American—would overwhelm the right. And slow-growing domestic traumas like economic unrest and increasing crime seemed more likely to emphasize division than community. Today the citizens of the United States have come together once more because of armed conflict and enemy attack.

Which sentence from the excerpt best reveals the context of the excerpt?

Once these disparate parts were held together by a common enemy, by the fault lines of world wars and the electrified fence of communism.
With the end of the cold war there was the creeping concern that without a focus for hatred and distrust, a sense of national identity would evaporate, that the left side of the hyphen—African-American, Mexican-American, Irish-American—would overwhelm the right.
And slow-growing domestic traumas like economic unrest and increasing crime seemed more likely to emphasize division than community.
Today the citizens of the United States have come together once more because of armed conflict and enemy attack.

Context is elucidated as the background information like setting, surroundings, environment, etc. that reveals the situations or circumstances in which a text if developed or constructed. It allows the readers to have a comprehensive understanding of the text.

As per the question, the above statement discloses the context of the given excerpt as it discusses the present circumstances(context) of the United States where 'disparate parts were held together by a common enemy.' The description of 'fault lines of world wars' and 'communism' clearly reveals the background situation, setting, environment(context) in which the narrative is constructed and hence, option A is the correct answer.