Flower color in a particular plant species is determined by one gene. The alleles of that gene can code for either red flowers or blue flowers. When a red plant and a blue plant are crossed, some of the offspring produce purple flowers. What is the genotype of the plants with purple flowers?

A. The genotype is BB because of incomplete dominance.

B. The genotype is Bb because of incomplete dominance.

C. The genotype is bb because of incomplete dominance.

D. The genotype has nothing to do with the color of the flower.