Complementation & Genetic Discussion

I’m working on a genetics question and need an explanation and answer to help me learn.

Cats with four ears result from a rare
recessive mutation in either of two genes
(A or B) required during ear development.
If two cats, each having four ears, have a
kitten that also has four ears, does this
mean complementation has occurred?
Why or why not? What does this mean about the types of mutation present in each of
the parents?