Answer:
her mother is giving warning
I’d say D is the best answer.
Breaking it up: "the reward of virtue is virtue;the I only way to have a friend is to be one .
"the reward of virtue is virtue". Meaning: when giving hope and kindness, hope and kindness shall be received.
"the I only way to have a friend is to be one ". Meaning: treat a friend as you would want a friend to treat you.
The Unicorn is always depicted as being chained, because according to folklore a free unicorn was a dangerous beast. Also, it was a Scottish symbol and they wanted to to show they conquered and ruled Scotland. It has a chain around its neck because it is considered to be an untamed animal.