Which one of the following genetic diseases is sex-linked ?

Royal haemophilia (hemophilia) is an X-linked (sex-linked) disorder; historically called the “royal disease” and classically transmitted as an X‑linked recessive trait, with females typically being carriers and affected males showing the phenotype [1]. By contrast, Tay–Sachs disease and cystic fibrosis are examples of autosomal recessive disorders, which are inherited independent of sex chromosomes and affect males and females equally [2]. Hypertension is generally a multifactorial condition involving polygenic and environmental factors rather than a single sex-linked gene [3]. Therefore, of the options given, Royal haemophilia is the sex-linked disease.

Sources

1. [1] https://apacwomen.ac.in/learning-resources/zoology/GENETICS.pdf
2. [2] https://www.sciencedirect.com/topics/immunology-and-microbiology/inheritance
3. [3] https://www.ncbi.nlm.nih.gov/books/NBK236037/