Modifying communication to fit situational, social, cultural, and relational contexts is known as?

Communication accommodation theory

Explanation:

Communication accommodation theory, developed by Howard Giles, the professor of communication at the University of California, is a theory of communication that explains the adjustments people make while communicating with others. This includes the changes in people's behavior caused by their tendency to adjust their communication to their partner and the degree to which people perceive their partner as appropriately adjusting to them. Made adjustments can be noticed in both verbal communication and gestures. All of this depends on situational, social, cultural and relational contexts.

- "the answers are a and b.  

when cullen speaks of planting while others reap, and standing "abject and mute," he is speaking about the racial injustices present in american society. as these injustices have changed over time, the american identity  has also shifted. those changes are, in turn, reflected in american literature."

last one is the answer