The HBB gene, which codes for the beta-globin part of hemoglobin, is located on chromosome 11. Mutations in the HBB gene can lead to β-thalassemia, a blood disorder that affects hemoglobin production.
Thus, the correct answer is (3) 11.

| List-I | List-II |
| (A) Thalassemia | (I) 47, XXY |
| (B) Klinefelter’s syndrome | (II) Sex-linked recessive disorder |
| (C) Turner’s syndrome | (III) 45, XO |
| (D) Colour blindness | (IV) Autosomal recessive disease |
| 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 |