C. if the homologous chromosome lacks the deletion.
Explanation:
Homologous chromosomes are the pair of chromosomes that are similar in their basic morphology and genetic constitutions. In a diploid organism like humans, two alleles of a particular gene are present on the corresponding loci on the homologous chromosome. Therefore, the deletion of a genetic segment from a chromosome will not be fatal if its homologous chromosome carries that genetic segment and has no deletion in that particular region.
For instance, the deletion of a genetic segment from a chromosome carrying the gene for eye color would be tolerated and would remain in the population if its homologous chromosome lacks deletion in this region and carries the allele for the eye color.
