Which detail from "The Magic Prison" foreshadows that the prison is becoming a palace again?

A. "Just then he heard a harsh, grating sound, as of rusty bolts sliding with difficulty out of their sockets; and then faint rays of light, not wider than a hair, began to shine between the heavy mirrors."

B. "The next day he was so hungry that he began to eat one of the old withered apples, and as he bit it he thought of the bird, his fellow prisoner."

C. "At last he heard, or thought he heard, a faint sound. He listened eagerly. It seemed to be some tiny creature not far from him trying to move about."

D. "One day, soon after this, the little bird fluttered up against the windowpane and beat his wings against it in a vain effort."

The detail from "The Magic Prison" that foreshadows that the prison is becoming a palace again is C. "At last he heard, or thought he heard, a faint sound. He listened eagerly. It seemed to be some tiny creature not far from him trying to move about."

Foreshadowing is a literary technique that is used to show or predict what will happen in the future in a literary work.

This technique is used when an author is trying to let the reader get a glimpse of what is to come by giving some details of what is to come.

Therefore, the correct answer is option C. This is because, the narrator hears a sound which in the prison was unheard of, but was common in the palace.