The percentage of the population suffering from serious mental illness is: (in $\%$)

Assertion $A$: The spleen is a large reservoir of lymphocytes.
Reason $R$: The spleen acts as a filter of the blood by trapping blood-borne microorganisms.
Which option is correct for Assertion $A$ and Reason $R$?

$A$ substance produced by an organism that inhibits the growth of another organism is called:

The diseases which occur at irregular intervals and locations are known as

The best $HLA$ (human leucocyte antigen) match for transplant in order of preference is:

Match the following diseases with their causative organisms and select the correct option.

Column-$I$ (Disease)	Column-$II$ (Causative Organism)
$(a)$ Typhoid	$(i)$ Wuchereria
$(b)$ Pneumonia	$(ii)$ Plasmodium
$(c)$ Filariasis	$(iii)$ Salmonella
$(d)$ Malaria	$(iv)$ Haemophilus