The right option is; ribosome
Ribosome is the cell structure that is most likely malfunctioning.
Ribosomes are membrane bound organelles that are located within all living cells. Ribosomes functions as the site of biological protein synthesis. The proteins produced by ribosomes are used for various cellular functions. Amino acids are joined together by ribosomes in the order specified by messenger RNA (mRNA) molecules. Ribosomes are made up of two major parts which are; (i) the large subunits, which join amino acids together to create a polypeptide chain, and (ii) the small ribosomal subunit which read the RNA (ribonucleic acid).