Question: In a certain population of squirrels that is in Hardy-Weinberg equilibrium, black color is a recessive phenotype present in 9 percent of the squirrels, and 91 percent are gray. What percentage of the population is homozygous dominant for this trait?
A: 21 percent
B: 30 percent
C: 49 percent
D: 70 percent
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.