Mr. Hammond inquires how his wife contracted this viral infection, since she has not come in contact with anyone who has shingles. You recall from microbiology that varicella zoster virus can remain in a chronic latent state in a host by:

the offspring would all be white. if the parents are both white flowers then they have the genotype rr, which when crossed results in an all white punnet square.

the answer is :

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.