Use the Following Information to Answer the Questions Below

Use the following information to answer the questions below.
A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa) , the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.
-You sample a population of butterflies and find that 42% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?

A) 0.09
B) 0.30
C) 0.49
D) 0.70
E) Allele frequency cannot be determined from this information.