Match the columns:

Column-$I$ (Blood group)	Column-$II$ (Antigen present)
$A$. $A$	$p$. $B$
$B$. $B$	$q$. $A$
$C$. $AB$	$r$. $A$ and $B$
$D$. $O$	$s$. $A, B$ and $O$
	$t$. $NIL$

(A-Q, B-P, C-R, D-T) The $ABO$ blood grouping system is based on the presence or absence of two surface antigens on the red blood cells,namely $A$ and $B$.
$1$. Blood group $A$ has antigen $A$ on the surface of RBCs.
$2$. Blood group $B$ has antigen $B$ on the surface of RBCs.
$3$. Blood group $AB$ has both antigens $A$ and $B$ on the surface of RBCs.
$4$. Blood group $O$ has no antigens $(NIL)$ on the surface of RBCs.
Therefore,the correct matching is: $(A-q), (B-p), (C-r), (D-t)$.