Aplastic anaemia is defined as anaemia caused by deficiency of all blood formed elements as a result of bone marrow failure.

• A. Megaloblastic anaemia
• B. Sickle cell anaemia
• C. Aplastic anaemia is anemia caused by deficiency of all blood formed elements due to bone marrow failure
• D. Iron-deficiency anaemia

Answer: (C)

Aplastic anaemia is defined by the bone marrow failing to produce all three blood cell lines—red cells, white cells, and platelets—leading to pancytopenia. The statement that describes aplastic anaemia as anemia caused by deficiency of all blood formed elements due to bone marrow failure matches this definition exactly, so it is the best choice.

Megaloblastic anaemia arises from impaired DNA synthesis (often due to B12 or folate deficiency), which causes macrocytic red cells but not a complete failure of the marrow to produce all blood elements. Sickle cell anaemia is a hemoglobinopathy with chronic hemolysis, not a marrow failure. Iron-deficiency anaemia stems from inadequate iron for hemoglobin synthesis, producing microcytic red cells, again not due to bone marrow failure.