Which of the Following Is an Example of an Epigenetic

Which of the following is an example of an epigenetic change in eukaryotes?

A) a loss of an AT base pair from a gene
B) the addition of methyl groups to cytosines in the promoter region of a gene
C) the substitution of an AT base pair by a GC base pair in a gene as a result of a mistake during DNA replication
D) a deletion that simultaneously removes two genes from the genome
E) None of these examples represents epigenetic changes.