Question: Huntington disease is an autosomal dominant trait that causes neurodegeneration later in life. Matt, who is too young to display the phenotype of Huntington disease, is married and has one son. Matt discovers that his mother has Huntington disease. Matt's father does not have Huntington's disease. Since Huntington's disease is a rare disorder, assume that Matt's mother is heterozygous and that his wife does not have Huntington's Disease. What is the probability Matt's son will get Huntington's disease?
A) 0.75 B) 0.5
C) 0.25 D) 0.125