Answer:
C: He is frustrated by his awareness of the injustice of slavery.
Explanation:
Context clues: " I envied my fellow-slaves for their stupidity", "wished myself a beast. I preferred the condition of the meanest reptile to my own", "Anything, no matter what, to get rid of thinking", "everlasting thinking of my condition that tormented me". based on the context clues, you can infer that He is frustrated by his awareness of the injustice of slavery because it shows many times he wished he had not been as smart as he was.
