The correct option is C Staining with ethidium bromide followed by exposure to UV radiations
Due to the action of restriction enzymes on the DNA molecule, fragments of DNA are formed.
Gel electrophoresis is carried out for separating these fragments of DNA. During the preparation of sample for gel electrophoresis, ethidium bromide and bromophenol blue are added.
DNA cannot fluoresce on its own. Ethidium bromide intercalates with the DNA. Ethidium bromide stains the DNA as bright orange bands when it is illuminated with UV rays. This is utilised for visualization of DNA molecules.
Bromophenol blue is known as the tracking dye as it runs fastest in the sample and tracks the migration of the sample during the run-time.