Given the task definition and input, reply with output. In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: A 71-year-old man presented with severe pancytopenia without any immature cells and with a medullar study suggestive of severe aplastic anemia. What would be the fundamental therapeutic approach?
Options: <1> Treatment with methylprednisolone at a dose of 1 g / Kg / day for 5 days. <2> Study of siblings and if any is HLA compatible, allogeneic transplant of hemopoietic progenitors. <3> Immunosuppressive therapy with cyclosporine and antitimocitic immunoglobulin. <4> Hemotherapeutic support. <5> Chemotherapy and if autologous transplant response of hemopoietic progenitors.
3