Read the given paragraph and answer the question:

Humans have 23 pairs of chromosomes. 22 pairs are exactly same in both males and females; these are the autosomes. A pair of X-chromosome are present in the female, whereas the presence of an X and Y chromosome are determinant of the male characteristic. A number of disorders in human beings have been found to be associated with the inheritance of changed or altered genes or chromosomes. Broadly, genetic disorder may be grouped into two categories disorders and Chromosomal disorders.

Which of the following is an example of a sex-linked disease?

Colour blindness

The correct answer is Option (2)- Colour blindness

Colour blindness is a genetic disorder that is inherited in an X-linked recessive pattern. This means that the gene responsible for colour vision is located on the X chromosome, and males have only one X chromosome, while females have two X chromosomes.

Ascaris lumbricoides, the causative agent of ascariasis, is the most common parasitic worm in humans.

Thalassemia  is an autosome-linked recessive blood disease transmitted from parents to the offspring when both the partners are unaffected carrier for the gene (or heterozygous).

Phenylketonuria is an inborn error of metabolism is inherited as an autosomal recessive trait. The affected individual lacks an enzyme that converts the amino acid phenylalanine into tyrosine.