Which disease is caused by a nematode?

Assertion $A$: In elephantiasis, body parts like legs, arms, and genital organs swell significantly.
Reason $R$: In chronic cases, filarial worms block the lymphatic vessels.
Which option is correct for Assertion $A$ and Reason $R$?

The adult $Wuchereria$ $bancrofti$ lives in:

Adults of $Wuchereria$ $bancrofti$ attack

Where do the infective larvae of Wuchereria bancrofti mature?

Filarial worms ($Wuchereria$ $bancrofti$ and $Wuchereria$ $malayi$) are known to: