In Drosophila melanogaster, a gene for eye color is located…

In Drosophila melanogaster, a gene for eye color is located on the X chromosome. The allele for red eyes (X^R) is dominant over the allele for white eyes (X^r). A female fruit fly with the genotype X^R X^r is crossed with a male with the genotype X^R Y. What proportion of their male offspring would you expect to have white eyes?