Assuming that the only function of Short gastrulation (Sog) in fruit flies is to regulate Decapentaplegic (Dpp), which of the following genetic interactions would you NOT expect to observe?

A) Mutant embryos lacking both Sog and Dpp phenotypically resemble those lacking only Dpp.
B) Partial loss of Sog suppresses the phenotype of partial loss of Dpp.
C) Gain of Dpp suppresses the phenotype of partial loss of Sog.
D) Gain of Sog suppresses the phenotype of gain of Dpp.