Correct option is B
pollution or shedding of pollen grains takes place at two-celled stage in 60% of angiosperms, in rest the generative cell divides to form two male gametes and Pollen is shed at three celled stage, the male gametes are non-motile and amoeboid, they are slightly an equal in size, such a pollen will be called a three celled pollen or mature male gametophyte.