The correct option is B Anther cells
Androgenesis
Androgenesis is a biological process where haploid plants are produced through the anther or microspore culture.
Anther cells
Anther cells contain haploid pollen grains. These cells are used in tissue culture to produce haploid plants. These plants are called androgenic haploid as they have been developed from the male gamete.
Callus cells
Plant callus is a massive growth of undifferentiated plant parenchyma cells.
Megaspore cells
Megaspores are haploid cells formed from the megaspore mother cells in ovules of plants. The megapore forms the female gametophyte, the embryo sac. These spores are not used in androgenesis.
Microspore cells
Microspores cells are the spores that develop into male gametophytes.