Which one of the following describes cross-pollination?A. The transfer of pollen grains from the anther to the stigma of the same flower.B. The transfer of pollen grains from the anther to the stigma of different flowers on plants of different kinds.C. The transfer of pollen grains from the anther to the stigma of another flower on the same plant.D.The transfer of pollen grains from the anther to the stigma of different flowers on plants of the same kind.