Step 1: Understanding Genetic Engineering.
Genetic engineering involves the manipulation of an organism's DNA to introduce desirable traits, cure diseases, or enhance productivity.
Step 2: Applications in Medical Treatment.
In medicine, genetic engineering is used in gene therapy, production of insulin, vaccines, monoclonal antibodies, and treatment of genetic disorders.
Step 3: Applications in Agriculture.
In agriculture, it is used to create genetically modified (GM) crops such as Bt cotton, Bt maize, and Golden Rice, which are pest-resistant or nutritionally enriched.
Step 4: Conclusion.
Since genetic engineering is applied in both medical treatment and agriculture, the correct option is (C) Both (A) and (B).