In Maize, Some Alleles at the Seed Coat Locus Influence

In maize, some alleles at the seed coat locus influence our ability to visually determine the endosperm color phenotype. Specifically, an opaque seed coat prevents us from seeing the endosperm within, while we can readily see the endosperm in seeds with transparent coats. The opaque coat color allele thus appears to mask the expression of endosperm color alleles, providing an example of

A) pleiotropy.
B) maternal effects.
C) polygenic inheritance.
D) codominance.
E) epistasis.