In angiosperms,microsporogenesis and megasporogenesis

Select the correct option that represents the organisms in descending order based on the number of chromosomes present in their meiocytes.

In $Agave$ (Century plant),vegetative propagation occurs through which of the following?

Identify the plant parts that consist of two generations,one within the other:
$(a)$ Pollen grains inside the anther
$(b)$ Germinated pollen grain with two male gametes
$(c)$ Seed inside the fruit
$(d)$ Embryo sac inside the ovule

After anther culture,some diploid plants are observed along with haploid plants. Which of the following parts induces the origin of the diploid plants?

Give the differences between Microsporangium and Megasporangium.