Which of the following is a single seeded cucurbit?

Chayote is a single-seeded cucurbit from the given options.
It is an edible plant belonging to the gourd family, Cucurbitaceae. The chayote fruit is mostly used cooked. When cooked, chayote is usually handled like a summer squash; it is generally lightly cooked to retain the crispy consistency. It is a good source of vitamin C.
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.