The correct answer is Option (3) -Down's Syndrome

Broadly, genetic disorders can be categorized into two main groups – Mendelian disorders and Chromosomal disorders. Mendelian disorders primarily result from alterations or mutations in single genes. These disorders are passed down to offspring following the principles of inheritance we have studied. The inheritance pattern of Mendelian disorders can be analyzed within a family through pedigree analysis. Some of the most common and prevalent Mendelian disorders include Haemophilia, Cystic fibrosis, Sickle-cell anemia, Color blindness, Phenylketonuria, Thalassemia, and more. It's worth noting that Mendelian disorders can be either dominant or recessive.

In contrast, chromosomal disorders occur due to the absence, excess, or abnormal arrangement of one or more chromosomes.Example : Down’s syndrome ,Turner’s syndrome etc.