This question deals with common misconceptions about what Hardy-Weinberg equilibrium (HWE) is. In peas, flower color is controlled by a single Mendelian locus with two alleles, R and r. RR plants have red flowers, rr have white flowers, and Rr have pink flowers. Let p equal frequency of R alleles and q equal frequency of ralleles. In the pea population under study, p = 0.50 and q = 0.50. You count the plants for their flower colors and find the following numbers: 

     Red: 40          Pink: 20     White: 40     Total = 100

Which one of the following statements is true:

None of the above.

We know that the pea population is in HWE at this locus because p + q = 1.

We know that the pea population is in HWE at this locus because the homozygotes are in equal numbers.

We know that the pea population is in HWE at this locus because p and q are equal.

We know that the pea population is in HWE because when we plug p and q into the HWE formula, we find that  p2 + 2pq + q2 = 0.25 + 0.50 + 0.25 = 1.