Solution

Hemophilia is an inherited bleeding disorder characterized by lacking or low levels of clotting factors resulting in the inability or impaired ability of blood clotting. Hemophilia A is caused by a deficiency of clotting factor VIII. Hemophilia B is also known as Christmas disease and is caused by a deficiency of clotting factor IX. Hemophilia C is caused by a deficiency of Factor XI blood clotting factor. Alkaptonuria is a genetic disorder which imparts inability to process the amino acids phenylalanine and tyrosine. Mutation in the HGD gene that codes for the enzyme homogentisate 1,2-dioxygenase is the cause of this disorder. A person homozygous for mutated allele accumulates an intermediate substance called homogentisic acid in the blood and tissues. The correct answer is "D".