hope this helps to answer your question
the question to number #9 is d
To answer this we need to remember how proteins are structured, the primary structure is just the polypeptide chain, secondary there is a certain folding level alpha-helix and folded beta-sheet, then is the tertiary structure that comes from a single polypeptide chain and is formed by secondary structures, finally, there is the quaternary structure where several polypeptide chains are involved as well as tertiary structures are folded together. Therefore taking this into consideration we can say that the correct answer is option two.
