The correct option is C Microspore
Microsporangium
The stamen (male reproductive part) is made up of a bilobed structure called anther, which is present at the tip of a long stalk called filament.
Each lobe of anther consists of two pollen sacs which are known as microsporangium.This bears the male gametophytes of microspores, which get developed into pollen grains.
Nucellus
Nucellus is made up of parenchymatous cells and forms the main body of ovule. It surrounds the embryo sac and provides nourishment to the developing embryo.
Stamen
Stamen is the male reproductive part of flowering plant or angiosperm.
Microspore
The microsporangia bear microspores formed as a result of meiosis in the microspore mother cell. These microspores get modified to form the pollen grains which bear the male gametes.
The microspores are called the male gametophytes of the flowering plants as they are gamete-bearing structures.
Final answer
c. Microspore