Hemophilia Is a Genetic Disease That Has Plagued the Royal

Hemophilia is a genetic disease that has plagued the royal houses of Europe since the time of Queen Victoria, who was a carrier. Her granddaughter, Alexandra, married Nicholas II, the last czar of imperial Russia. Alexandra was a carrier for hemophilia, but Nicholas was normal. Their son, Alexis, was afflicted with the disease. Based on this scenario, it is most likely that

A) each of the sisters had a 50% chance of being a carrier of the gene.
B) at least one of the sisters had hemophilia.
C) all four sisters were carriers of the hemophilia gene.
D) Alexis inherited the hemophilia gene from Nicholas II.
E) none of the four sisters carried the hemophilia gene.