In the purple penguin, an allelic series occurs at the p locus on an autosome. all alleles affect the color of feathers: pd = dark-purple, pm = medium-purple, pl = light-purple, and pvl = very pale purple. the order of dominance is pd > pm > pl > pvl. if a pl/pvl female is crossed to a pd/pmmale, the ratio of phenotypes expected among the baby penguins would be:

a) 2 dark: 1 light: 1 very pale.

b) 2 dark: 1 medium: 1 light.

c) 1 dark: 1 medium.

d) 1 dark: 1 medium: 1 light: 1 very pale.

e) 1 medium: 1 light.