Cotton, seed-hair fibre (testa) of a variety of plants of genus Gossypium, belonging to Hibiscus or mallow, family (Malvaceae) and native to most subtropical parts of world.
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around seeds of cotton plants. The fiber is almost pure cellulose. Under natural conditions, cotton bolls will tend to increase dispersion of seeds. So, fibres of Gosssypium are out growth of testa and not out growth of pericarp, pappus hair and bast fibres.
Therefore, correct answer is option C.