Development of female gametophyte directly from megaspore mother cell without meiosis is called
Apospory
In apospory, the embryo sac or female gametophyte develops from a diploid sporophytic cell of the ovule such as the megaspore mother cell without meiosis. Thus the egg within the embryo sac is diploid and develops into a diploid embryo.
Final answer
b. Apospory.