Answer:
The correct answer will be option C- A structure upon which proteins are assembled.
Step-by-step explanation:
A ribosome is a complex molecule machine formed of proteins and rRNA molecules which acts as a site for the synthesis of the proteins.
These ribosomes are present in the cell as a free entity suspended in the cytosol or attached to the endoplasmic reticulum.
Each ribosome is made up of a large and small component which translates the information coded in the mRNA in the form of codons to amino acids which join to form proteins.
Thus, option- C is the correct answer.