Which of the following sex-linked disorders was common among the royal families of Europe, and all of the affected males could trace their ancestry to Queen Victoria of England?

A) fragile X syndrome
B) hemophilia
C) color-blindness
D) Duchenne muscular dystrophy
E) None of the answer choices is true.

Hemophilia is a sex-linked disorder, meaning it is carried on the X chromosome. Queen Victoria of England was a carrier of the gene for hemophilia, and passed it on to several of her children, who then passed it on to their offspring in various royal families throughout Europe. This is known as the "royal disease." The other disorders listed (fragile X syndrome, color-blindness, and Duchenne muscular dystrophy) can also be sex-linked, but there is no known relationship between them and the European royal families.