Reverse transcriptase is a type of enzyme which is present in many RNA based viruses such as retrovirus that are found in humans. Reterovirus uses reverse transcriptase enzyme in order to change their single stranded DNA into double stranded DNA. The process of such type of conversion is called reverse transcription. In viruses such as reterovirus, reverse transcriptase allows the virus to insert its DNA to the host cell's DNA, which helps the virus to produce more viruses.
The answer is C. The Scientific Method is the method used whenever you want to explain or figure out anything scientifically. It involves hypothesis, experiments, and conclusions