In which insect family wing venation is reduced to a single anterior vein?

Answer: Option C

In Chalcididae insect family wing venation is reduced to a single anterior vein.
The Chalcididae is a moderate-sized family within the Chalcidoidea, composed mostly of parasitoids and a few hyperparasitoids.
They are often black with yellow, red, or white markings, rarely brilliantly metallic, with a robust mesosoma and very strong sculpturing. The hind femora are often greatly enlarged, with a row of teeth or serrations along the lower margin. Chalcids are recognized by the reduced venation of the wings.