Hello,
The answer is option C "comment".
Reason:
The option comment allows you to give your opinion on someone else's work (or document). Its not option B because bookmark allows you to save your space in a document. Its also not option D because highlight allows you to mark important information in a document. Its also not option A because annotation has to do with grammar or writing.
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit