In Laboratory Mice,the "Short Tail" Phenotype Is Dominant to the Wild-Type

Multiple Choice

In laboratory mice,the "short tail" phenotype is dominant to the wild-type ("long tail") phenotype.However,crosses between any two short-tailed mice always produce mixtures of short- and long-tailed offspring.Assuming that tail length is controlled by a single locus,a likely explanation for these results is that the "short tail" allele is:

A) a codominant allele.
B) a dominant lethal allele.
C) haploinsufficient.
D) an incompletely dominant allele.
E) a recessive lethal allele.