The Following Pedigree Shows the Inheritance of Attached Earlobes (Black

Multiple Choice

The following pedigree shows the inheritance of attached earlobes (black symbols) and unattached earlobes (white symbol) .Both alternative phenotypes are quite common in human populations. If the phenotypes are determined by alleles of one gene,then attached earlobes are inherited as:

A) an autosomal dominant trait.
B) an autosomal recessive trait.
C) a dominant trait that could be either autosomal or X-linked.
D) a recessive trait that could be either autosomal or X-linked.
E) an X-linked dominant trait.