Within Human Chromosomes There Are Regions of Highly Concentrated GC

Within human chromosomes there are regions of highly concentrated GC content. Many of the cytosine residues that fall within CpG dinucleotide sequences are methylated at the 5 position (m⁵CpG) . Which of the following best explains why these methyl-CpG sequences are exceptionally prone to mutation?

A) deamination of m5C produces T
B) histones bind less tightly to m5C sequences than to other sequences
C) homologous recombination occurs preferentially at m5C sequences
D) methylation of C directly changes its basepairing properties
E) methylation of C directly interfere with basepairing during DNA replication