In a population at Hardy–Weinberg equilibrium, the frequency of allele $C$ is $p$ and the frequency of allele $c$ is $q$ (with $p+q=1$). What is the expected genotype frequency of $cc$?

• A. $2pq$
• B. $q^2$
• C. $p^2$
• D. $p+q$

Answer: (B)