What is the difference between a gene and an allele?

A gene is hereditary information to one, and an allele is just a variant form of a gene. So, I guess you could say an allele is a specific form of a gene.

the answer would be..

b. sucking

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).   so the answer is a.