Question

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 two such plants are crossed, however, some of the offspring produce purple flowers. What is the genotype of the plants with purple flowers?

an allele for red flowers on both homologous chromosomes
two alleles for red flowers on one homologous chromosomes, and two alleles for blue flowers on the other.
an allele for red flowers on one homologous chromosome and an allele for blue flowers on the other
an allel