Why are relatively few inherited disorders caused by two dominant alleles?

Why are relatively few inherited disorders caused by two dominant alleles?
A) Because most disorders caused by dominant alleles lead to sterility which means the dominant allele will not be passed on.
B) Because genetic testing can more readily identify dominant rather than recessive alleles, genetic counseling has more successfully reduced the incidence of disorders caused by dominant alleles.
C) Because every person with one of the dominant alleles will have the disorder, and people with most of these disorders do not usually live long enough to reproduce, so the allele will not be passed on.
D) Because individuals carrying dominant alleles for a disorder are less likely to actually have the disorder than individuals carrying a recessive allele for a disorder.