The alternative forms of a gene are called

Answer: Option C

The alternative forms of a gene are called Alleles.
"Allele" is the word that we use to describe the alternative form or versions of a gene.
Alleles are matching genes; one from our biological mother, and one from our biological father. One has two copies of every gene (strings of code that drive some biological function on our chromosomes). They can be identical, but they can often have slight differences.