Answer:
b. Aa
Explanation:
The presence of both dominant and recessive progeny suggests that the dominant parent should be heterozygous for the trait under study. Let's assume that the genotype of the dominant parent is "Aa" and that of the recessive parent is "aa". A cross between these two parents should obtain both dominant and recessive progeny in 1:1 ratio.
According to the given information, the phenotype ratio of the obtained progeny was around 1 dominant: 1 recessive.