Correct Option: D

Edible plant stems are one part of plants that are eaten by humans. Most plants are made up of roots, stems, leaves, flowers, buds and produce fruits containing seeds. The edible portion in an onion is swollen leaves with a bit of stem. They are bulbs which, like garlic and leeks, are modified stems in which the primary storage tissue is expanded leaf bases. They come in white, yellow, and red varieties.