This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Test used to differentiate between chromosomal pattern of normal cell and cancer cell? 
Select and explain. 
A. FISH, B. PCR, C. Karyotyping, D. Comparative genomic hybridization
D: Comparative genomic hybridization
Answer: D: Comparative genomic hybridization 
Explanation: None