This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Pathology
F body is 
Select and explain. 
A. Y chromatin, B. X chromatin, C. Chromosome 1, D. Chromosome 21
A: Y chromatin
Answer: A: Y chromatin 
Explanation: Ans. (a) Y chromatin(Ref: Emery Genetics)Quinacrine, a fluorescence dye, binds strongly to the Y chromosome forming a bright fluorescent spot (F body). This is clearly visible in stained interphase cells from various tissues from the human male and in mature spermatozoa