Infective juvenile of Wuchereria is

The correct option is C Third stage juvenile

The third-stage infective larvae (L3i) enter the blood through the wound made by the mosquito. They then migrate to the nearest lymph gland where they mature into the thread like adult worms about 3 months to 1 year later. The average incubation time before patency is about 15 months. The mature adults can survive for 5 to 10 years and the damage of the lymphatic vessels they cause and the immune system's response to their presence (and that of microfilaria and newly innoculated L3i) can result in the various pathologies

So, the correct answer is 'Third stage juvenile'.