Linkage Disequilibrium Is Defined by Which of the Following

Linkage disequilibrium is defined by which of the following?

A) positions in the genome where people vary by a single nucleotide base
B) the probability that two genes are linked
C) the nonrandom association between alleles in a haplotype
D) the occurrence of two alleles in the repulsion configuration
E) crossing over that occurs between two genes that are located close to each other