<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:An investigator is studying collagen synthesis in human fibroblast cells. Using a fluorescent tag, α-collagen chains are identified and then monitored as they travel through the rough endoplasmic reticulum, the Golgi apparatus, and eventually into the extracellular space. Which of the following steps in collagen synthesis occurs extracellularly?? A: Glycosylation of pro-α chains, B: Hydroxylation of proline and lysine, C: Cleavage of procollagen C- and N-terminals, D: Triple-helix formation, E: Translation of pro-α chains,  <response>: This is a question about the steps involved in collagen synthesis and where they occur within the cell. The question is asking specifically about which step occurs extracellularly, outside of the cell. Based on the background provided, we know that pro-α collagen chains are tagged and tracked as they move through the ER and Golgi, which are intracellular organelles. So the step must occur after the chains are secreted from the cell. Looking at the choices, cleavage of the procollagen C- and N-terminals is the only option that would occur after secretion into the extracellular space.C: Cleavage of procollagen C- and N-terminals 