Match the columns:

Column $I$	Column $II$
$(a)$ Sickle cell anaemia	$(p)$ Homogentisic acid
$(b)$ Alkaptonuria	$(q)$ Lack of Melanin
$(c)$ Albinism	$(r)$ Accumulation of Amino acid
$(d)$ Phenylketonuria	$(s)$ Defective haemoglobin

(A) $(a-s), (b-p), (c-q), (d-r)$
Explanation:
$1$. Sickle cell anaemia $(a)$ is caused by the production of defective haemoglobin $(s)$ due to a point mutation in the $\beta$-globin gene.
$2$. Alkaptonuria $(b)$ is a metabolic disorder characterized by the accumulation of homogentisic acid $(p)$ in the urine.
$3$. Albinism $(c)$ is a genetic condition resulting in the lack of melanin $(q)$ pigment in skin,hair,and eyes.
$4$. Phenylketonuria $(d)$ is an inborn error of metabolism where the enzyme phenylalanine hydroxylase is deficient,leading to the accumulation of phenylalanine (an amino acid) $(r)$ in the body.