Usually, the word invasion is related to words such as enemy, or to actions such taking possession of other people's propety or harming someone. Taking into account this context of the word invasion, the best example of invasion literature would be A: An unknown enemy takes over a small town, and average citizens are forced to fight for their freedom. In this sentence, the use of the word enemy and the action of taking over a small town make a reference to situations that currently happen during invasions.