Answer:
A2
Explanation:
According to Mendel's law of inheritance, dominant allele is the one which gets expressed even in heterozygous condition. It is able to mask the effect of recessive allele.
Here, A1 is responsible for dark brown color and A2 is responsible for light brown color. In homozygous condition, both the alleles show their respective phenotypes. However, in heterozygous condition (A1A2), light brown color is expressed. Since light brown color is due to A2 allele, it is the dominant one.
