Pedigrees help geneticists understand how traits are inherited between generations. Red-green color blindness is a s3x-linked disorder that is determined by a recessive allele on the X chromosome.

Briand is a filled-in square.

If Brian has a son who is color-blind, what is known about the genotype of the son's mother?
She must have at least one allele for color blindness.
She must have two alleles for color blindness.
She cannot be h0m0 zyg0us recessive for the gene for color blindness.
She cannot be a heter0 zyg0us carrier of the gene for color blindness.

THE ANSWER IS A. I LOOKED UP AND THE OTHER BRAINLY QUESTION SAID IT WAS B AND I GOT IT WRONG AND NOW I HAVE 96% SCORE.