1. What does literal mean?

Literal language uses words exactly according to their conventionally accepted meanings or denotation

another explination is absolute (used to emphasize that a strong expression is deliberately chosen to convey one's feelings).

representing the exact words of the original text. exactly copied; realistic as opposed to abstract or impressionistic.

Explanation:

the answer would be a

- "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."