Amphidiploid cucurbit is

Answer: Option B

Amphidiploid cucurbit is Pumpkin.
Amphidiploid is an interspecific hybrid having a complete diploid chromosome set from each parent form. Or in other words, it can be called an organism produced by the hybridization of two species followed by chromosome doubling.
A pumpkin is a cultivar of winter squash that is round with smooth, slightly ribbed skin and is most often deep yellow to orange in coloration. The thick shell contains seeds and pulp.