Answer:
It is codorminace.
Explanation:
Codorminace is a type of inheritance relationship in which the offspring receive one allele or gene from the father and another gene from the mother and the two allele inherited are not receive rather they are dorminant in the offspring or they are not masked but they are both expressed in the offspring.
From the question, it could be discovered that the offsprings inherit dark brown gene from the father and golden brown from the mother , the two are expressed at they same time and that is why the children shades from light to dark brown.
All the conditions are in the pic i attached.
If u still need help send the choices in the comments and I’ll answer:)
Skin muscle etc.yk look it up too :()