Correct option is : (D) Phenyl ketonuria
Down's syndrome: This is a chromosomal disorder caused by the presence of an extra copy of chromosome 21 (Trisomy 21). Therefore, it is a chromosomal disorder.
Klinefelter's syndrome: This is also a chromosomal disorder caused by the presence of an extra X chromosome in males (XXY). Thus, it is classified as a chromosomal disorder.
Turner's syndrome: This is a chromosomal disorder that occurs when a female has only one X chromosome (45,X). Therefore, it is a chromosomal disorder.
Phenylketonuria : Phenylketonuria (PKU) is a metabolic disorder. It is an autosomal recessive disorder. PKU is not a chromosomal disorder.
