question: Q:A 4-year-old child presents to the pediatrician with mental retardation, ataxia, and inappropriate laughter. The parents of the child decide to have the family undergo genetic testing to determine what the cause may be. The results came back and all three had no mutations that would have caused this constellation of symptoms in the child. Karyotyping was performed as well and showed no deletions, insertions, or gene translocations. Based on the symptoms, the child was diagnosed with Angelman syndrome. Which of the following genetic terms could best describe the mechanism for the disorder in the child?? 
  {'A': 'Codominance', 'B': 'Incomplete penetrance', 'C': 'Anticipation', 'D': 'Uniparental disomy', 'E': 'Variable expressivity'},