Rhizome is a modified subterranean stem of a plant that is usually found underground, often sending out roots and shoots from its nodes. Rhizomes are also called as creeping root stalks and root stocks. Rhizomes develop from axillary buds and are diageotropic or grow perpendicular to the force of gravity. The rhizome also retains the ability to allow new shoots to grow upwards. Examples of plants that are propagated this way include hops, Asparagus, ginger, Irises, Lily of the Valley, Canna and sympodial orchids. Some rhizomes are used directly in cooking, including ginger, turmeric, galangal, and finger-root. Ginger (Zingiber officinale) is a flowering plant in the family Zingiberaceae whose rhizome, ginger root or simply ginger is widely used as a spice or a medicine. So, ginger is a rhizome and not tuber, bulb and corn.
Thus, the correct answer is option A.