Answer:
The correct answer is option A "incomplete dominance".
Explanation:
In this example, after making a cross-breeding between two different snakes, all the baby pythons were brown with a faint diamond pattern. This phenotype is different of the phenotype of the two parents (a solid brown male python, and a tan black diamond female), and corresponds to an intermediate phenotype between them. This a characteristic inheritance pattern as of incomplete dominance, at which no allele is completely expressed over the other resulting in the offspring having a third intermediate phenotype.
