The correct option is B Trichomes on seed coat of Gossypium
Cotton taken for commercial purpose is a soft, fluffy staple fibre growing in a boll from trichomes on the seed coat of the plants of the genus Gossypium of the family Malvaceae. The cotton fibre is pure cellulose and under natural conditions, these bolls tend to increase the dispersal of the seeds.
Thus, the correct answer is option B.