Which Statement Regarding Partial Chromosomal Deletions or Duplications Reflects the Cause

Multiple Choice

Which statement regarding partial chromosomal deletions or duplications reflects the cause of manifestations?

A) They result in either a triple dose of some gene alleles or a single dose of some alleles.
B) They usually result in fewer or milder manifestations than do trisomies or monosomies.
C) The manifestations are unpredictable because they commonly vary depending on parental origin.
D) General prenatal chromosomal analysis has resulted in fewer children being born with these problems.