Context: This passage describes the albinism trait in rats:

In a group of rats, some individuals have albinism and others do not. In this group, the gene for the albinism trait has two alleles. The allele A is for not having albinism, and the allele a is for having albinism.
Abigail, a rat from this group, does not have albinism. Abigail has one allele for not having albinism and one allele for having albinism.
Based on this information, what is Abigail's genotype for the albinism gene?
A. Aa
B. not having albinism
Select the correct answer from the given choices and respond with the letter of the chosen option.

A