Increased RBC`s in the blood leads to a condition called polycythemia. Polycythemia is a condition characterized by an abnormal increase in the number of red blood cells in the blood. This can occur due to various reasons, such as chronic exposure to high altitudes, smoking, certain types of tumors, or by certain genetic mutations.
Option 1, anemia, is incorrect as it refers to a condition where there is a decrease in the number of red blood cells or a decrease in hemoglobin levels.
Option 2, hemophilia, is incorrect as it refers to a genetic disorder characterized by impaired blood clotting.
Option 4, leukemia, is incorrect as it refers to cancer of the blood cells, particularly involving the white blood cells.
Therefore, the correct answer is option 3, polycythemia.