In a disease associated with a nucleotide repeat, anticipation is often noticed in subsequent ...

In a disease associated with a nucleotide repeat, anticipation is often noticed in subsequent generations, usually associated with a more severe phenotype. Which of the following is a more likely cause of anticipation?
 
  A) The CAG alleles with a high number of repeats are unstable and change size from generation
  to generation.
  B) Subtle phenotypic nuances are more often sought by a physician.
  C) Family members are exposed to the same mutagens.
  D) Highly repeated sequences are expressed more often.
  E) The sequences have greater stability in later generations.