<span>Proper adjectives have their initial letter capitalised,
for example American - derived from a proper noun America - or Victorian - derived from (queen) Victoria.
Common adjectives, on the contrary, don't have </span><span>their initial letter capitalised</span>, for example green, empty, colourful. Just remember that "common adjective" is not a scientific term used by linguists, it is informal.
I think the answer is d - author
C. Kind - She is well known for being innocent and quiet, almost no one knows she even exists to a certain extent. She couldn't be cruel, or spiteful, but maybe adventurous towards the end of the story. But if I were answering this, I would answer kind because that's all she ever knew.
B. there is a simile to help the reader visualize what the device looks like.