Answer
D.
Work Step by Step
The frequency of the white allele, q, is the square root of the frequency of white flowers. The frequency of white flowers is the whole population minus the red flower frequency=1.0-0.91=0.09. The square root of 0.09 is 0.3. p+q=red allele frequency+white allele frequency=1=red frequency+0.3. Solving, we find that the red allele frequency is 0.7.
