Genes are sections of DNA that carry the information for a trait and can produce either a protein or RNA. For example, the gene for the blood type has the information for the production of a protein found on the surface of blood cells.
Alleles are different versions of the same gene. For example, the gene for the blood type can produce protein A, protein B, or neither of them.
Each person has two alleles of a gene because they inherit one copy from their mother and another from their father, and these copies can be the same or different.
Chromosomes are molecules of condensed DNA, helped by proteins in the case of eukaryotic organisms.
This means that the sentence that best describes the relationship between these three words is D) alleles are the options for genes and genes are found on chromosomes