The correct option is D Haemophilia and colour blindness
Mutation refers to any sudden, inheritable change in the genetic material of an organism.
X and Y are sex chromosomes.
Haemophilia is an inherited bleeding disorder wherein a person lacks or has low levels of certain proteins called ‘clotting factors’. This results in people bleeding continuously as their blood is not able to clot properly.
The inability of the blood to clot is brought about by the mutation or change in the genes located on the sex chromosome X, which carries the genetic instruction of how to synthesise the clotting factors needed to form a blood clot.
Colour blindness is another genetic disorder in which the patient is unable to produce functional cones (proteins that help in colour vision) in his eyes. So, the affected person is unable to distinguish between specific colours. This is caused due to mutation of genes encoding cones present on the X chromosome.
Since these genes are located only on the X chromosome, it makes haemophilia and colour blindness, X-linked diseases.
Phenylketonuria, thalassemia and sickle cell anaemia are autosomal recessive disorders.