. . . . . . . . is the only cultivated member of cucurbitaceae family which is single seeded.

Answer: Option D

Chayote is the only cultivated member of cucurbitaceae family which is single-seeded.
Chayote is an edible plant belonging to the gourd family, Cucurbitaceae.
The fruit is roughly pear-shaped, somewhat flattened and with coarse wrinkles, ranging from 10 to 25 cm in length. It looks like a green pear and it has a thin, green skin fused with the green to white flesh and a single, large, flattened pit with a single but edible seed. The flesh has a fairly bland taste and the texture is described as a cross between a potato and a cucumber.