I think its a , but double check because i dont want it to be wrong .
Answer:Human height
Explanation:
Inheritance patterns are often more complex than predicted by simple mendalian genetics. When Mendel studied some phenotypic characters, like the human skin color and height, they were found to be an addictive effect of two or more genes on a single phenotypic character. These are called quantitative characters, which usually indicates polygenic inheritance.
The human height is an example of quantitative character, it is controlled by at least 3 genes having 6 alleles. 3 genes with 6 alleles from both parent can give rise to wide range of phenotypic character (heights).
I believe it's the first one.