Match List I with List II

List I		List II
A	Down’s syndrome	I	11th chormosome
B	α-Thalassemia	II	‘X’ chromosome
C	β-Thalassemia	III	21st chromosome
D	Klinefelter’s syndrome	IV	16th chromosome

Choose the correct answer from the options given below:

To match List I (genetic disorders/syndromes) with List II (chromosomes associated with them), we can analyze each condition one by one:

1. A. Down’s syndrome: This is a genetic disorder caused by the presence of an individual's third copy of chromosome 21 (trisomy 21). Therefore, A matches with III (21^st chromosome).

2. B. α-Thalassemia: Alpha thalassemia is a type of thalassemia caused by mutations in the HBA1 and HBA2 genes, which are located on chromosome 16. Therefore, B matches with IV (16^th chromosome).

3. C. β-Thalassemia: Beta thalassemia is caused by mutations in the HBB gene on chromosome 11. Therefore, C matches with I (11^th chromosome).

4. D. Klinefelter’s syndrome: This is a genetic condition in males where they have an extra X chromosome, resulting in an XXY karyotype. Therefore, D matches with II (‘X’ chromosome).

Putting it all together, the correct matching is:
A-III, B-IV, C-I, D-II