Answer: The correct option is D) Ribosomes.
Ribosomes are the complex molecular machinery, which are present as free form in the cytoplasm and bound form with endoplasmic reticulum. They serve as the site of protein synthesis, which is called as translation. For protein synthesis, amino acids join together at ribosomes with the help of peptide bond.
Ribosomes have two subunits, which are smaller and larger subunits. Joining of amino acids take place at the larger subunit of ribosome. Whereas, smaller subunit reads the mRNA frame.