Blood disorders can affect the production and function of blood cells. Consider the following statements regarding various blood disorders:

A. Anemia is characterized by a decrease in the number of erythrocytes or hemoglobin concentration, leading to reduced oxygen-carrying capacity.

B. Leukemia is a malignancy of hematopoietic tissues characterized by an overproduction of non-functional leukocytes.

C. Thrombocytopenia refers to an elevated platelet count, which can lead to increased risk of clotting and thrombus formation.

D. Hemophilia is a genetic disorder that affects the clotting cascade, leading to increased bleeding tendency due to deficiencies in clotting factors.

Which one of the following options represents the correct combination of the statements?