Choice A rationale:

Leukemia is not a benign disorder; it is a malignant cancer of the blood and bone marrow.

Benign disorders do not involve uncontrolled cell proliferation.

Choice B rationale:

Leukemia is not characterized by the proliferation of normal white blood cells.

It involves the abnormal proliferation of immature white blood cells.

Choice C rationale:

This is the correct answer.

Leukemia can lead to complications such as infection, bleeding, and anemia.

The abnormal white blood cells in leukemia crowd out normal blood cells, leading to a decreased ability to fight infections (due to low normal white blood cells), increased bleeding tendencies (due to low platelets), and anemia (due to low red blood cells)

Choice D rationale:

Leukemia is not caused by exposure to a single specific chemical.

Its exact cause is often unknown, but it is believed to involve a combination of genetic and environmental factors.