This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Single Gene Disorders, Subject name: Pathology
In classical Mendelian inheritance, autosomal dominant disease characterized by: 
Select and explain. 
A. Complete penetrance, B. Parents are unaffected, C. Very early onset in life, D. Variable expressivity
D: Variable expressivity
Answer: D: Variable expressivity 
Explanation: Autosomal dominant disease -Variable expressivity -Incomplete penetrance -Both parents are affected -No skipping of generations