This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Basics of genetics, Subject name: Biochemistry
Which of the following is the smallest autosome? 
Select and explain. 
A. Chromosome 1, B. Y chromosome, C. Chromosome 21, D. Chromosome 22
C: Chromosome 21
Answer: C: Chromosome 21 
Explanation: Karyotyping Chromosome visualisation technique in which chromosome pairs are arranged in decreasing order of size except chromosome 21 & 22. Feature Chromosome no. The largest chromosome 1 The smallest chromosome Y The smallest autosome 21