Final answer:
The person most likely to suffer from red-green colorblindness is Lisa with genotype X^R Y because males have only one X chromosome and if that chromosome carries the gene for colorblindness, they will be colorblind.
Step-by-step explanation:
Red-green colorblindness is a sex-linked, recessive trait. Typically, males are more likely to be colorblind because they have only one X chromosome, and if the colorblind gene is present, there is no matching allele on another X chromosome to mask it. Females can be carriers of the trait without being colorblind themselves, because they have two X chromosomes, and the non-colorblind allele would provide the dominant phenotype.
In the given genotypes:
a) John with genotype X^R X^R would not be colorblind, as both alleles are normal.
b) Mary with genotype X^R X^r is a carrier but not colorblind due to the presence of a normal allele.
c) Chris with genotype X^r X^r is a female who would be colorblind, having two recessive alleles.
d) Lisa with genotype X^R Y is most likely to suffer from red-green colorblindness because there is no second X chromosome with a normal vision allele to mask the potential colorblindness gene on the X chromosome.