Leaves become modified into spines in Allium, Gossypium, Opuntia, Pisum?

Opuntia is a genus in the cactus family, Cactaceae. The most common culinary species is the Indian fig, Opuntia. Most culinary uses of the term "prickly pear" refer to this species. Opuntia typically grow with flat, rounded cladodes (also called as platyclades) armed with two kinds of spines; large, smooth, fixed spines and small, hairlike prickles called as glochids, that easily penetrate skin and detach from the plant. Many types of prickly pears grow into dense, tangled structures. Thus, the correct answer is option C.