What is linkage disequilibrium (LD) and which factors can generate it in populations?

• A. Non-random association of alleles at different loci; LD arises from genetic drift, selection, admixture, and physical linkage.
• B. Random association of alleles; LD arises from migration only.
• C. Correlation of allele frequencies within a single locus; LD arises from mutation alone.
• D. Non-random recombination within a locus; LD arises from recombination only.

Answer: (B)