The correct option is D both a and b
Downstream processing is a series of processes that the product has to undergo before it is ready for marketing as a finished product. It includes separation and purification. The product also has to be formulated with suitable preservatives.
DNA spooling is not a part of downstream processing. DNA spooling isolates long strands of DNA from a solution. In this technique, charged DNA molecules can be scooped up and swirled around a glass rod or wooden spooling stick. DNA spooling is done to isolate the genetic material.