Example of intergenic gene interaction is/are

Match List-$I$ with List-$II$ :

List-$I$	List-$II$
$A$. Incomplete Dominance	$I$. Human skin colour
$B$. Co-dominance	$II$. Inheritance of flower colour in Antirrhinum sp.
$C$. Pleiotropy	$III$. Phenylketonuria disease in humans
$D$. Polygenic inheritance	$IV$. $ABO$ blood group

Choose the correct answer from the options given below :

In hexaploid wheat, what are the haploid $(n)$ and basic $(x)$ chromosome numbers?

Select the incorrect pair.

$ABO$ blood type in man is an example of
$A$. Pleiotropy
$B$. Incomplete dominance
$C$. Co-dominance
$D$. Multiple allelism
Select the code for the correct answer from the options given below.

Sickle-cell anemia has not been eliminated from the African population because,........