Identifying Polygenic Traits

Which of the following sets of data provides evidence that a trait is polygenic?

I. The genotypes at loci A, B, and C each produce a protein that influences the length of an organism by an average of 0.6, 0.4, and 0.3 cm, respectively.

II. Three different alleles of gene D affect the length of an organism by an average of 0.6, 0.4, and 0.3 cm, respectively.

III. Loci E, F, and G each modulate an independent pathway that plays a role in determining the length of an organism.