Interferons are proteins that...

Given below are two statements. Select the most appropriate answer from the given options.
Statement-$I$: $T$-lymphocytes have $4$ subtypes as helper,killer,memory,and suppressor $T$-cells.
Statement-$II$: $B$-lymphocytes mature in the thymus and are responsible for cell-mediated immunity.

The interferon which is synthesized by $WBC$ is known as

The lack of $B$-cells and $T$-cells is known as:

$IFN$ (Interferons) are . . . . . . ?

Which type$(s)$ of interferon is/are present in humans?