Hemophilia A is a genetic disorder inherited as an X-linked recessive trait. It is associated with serious bleeding. Which statement CORRECTLY describes the reason for this disease?

A)
It occurs due to a change in the shape of blood cells.

B)
It occurs due to the presence of abnormal hemoglobin in blood.

C)
It occurs due to the reduction in the number of white blood cells.

D)
It occurs due to a defective protein, which slows down coagulation.