Correct Option: C

Haemophilia is a sex linked disease (linked with X chromosomes). In this disease, blood lacks the thromboplastin protein which causes blood clotting during injury. In normal human, blood clots in 2-6 min. While in haemophilic human, it may take from 3 hrs to 24 hrs due to which death may occur. This disease was Ist discovered by Jon Catto in 1803. The most famous families in which the inheritance of this disease was found were the Royal families of Britain & Russia, so it is also called Royal disease.