What is the Hardy-Weinberg equation and what do p and q represent?

• A. p + q = 1; p^2 + 2pq + q^2 = 1; p and q are allele frequencies; p^2, 2pq, q^2 are genotype frequencies.
• B. p^2 + 2pq + q^2 = 1; p and q are genotype frequencies.
• C. p + q = 1; p^2 + 2pq + q^2 = 1; p and q are genotype frequencies.
• D. p + q = 2; p^2 + q^2 = 1.

Answer: (A)