Final answer:
Aplastic anemia can be caused by both immune-mediated factors and acute hepatitis, as they both contribute to the destruction of bone marrow cells responsible for producing blood cells.
Step-by-step explanation:
Aplastic anemia is a condition characterized by deficient numbers of RBC stem cells. It can be caused by various factors such as inheritance, radiation, medication, chemotherapy, or infection. One of the causes of aplastic anemia is immune-mediated, meaning that the immune system attacks and destroys the bone marrow cells responsible for producing blood cells. Acute hepatitis, an inflammation of the liver, can also trigger aplastic anemia. Therefore, the correct answer is 3) Both immune-mediated and acute hepatitis.