Final answer:
In a plant's male reproductive organs, development of pollen takes place in a structure known as the anther.
Option a is correct.
Step-by-step explanation:
Pollen in a plant's male reproductive organs develops in a structure known as the anther, which is part of the stamen.
The anther is a component of the stamen and is responsible for producing and housing the microspores, which eventually develop into pollen grains.
While the stamen is the collective term for the male reproductive part of a flower, consisting of both the filament and the anther, it is specifically within the anther that pollen is produced.
Contrary to the anther, the stigma is a part of the carpel or pistil, which is the female reproductive structure and serves as a landing platform for pollen during the pollination process.
The filament is the stalk that holds the anther up to facilitate pollination, and the ovule is part of the female reproductive organs within the ovary where the egg cells develop.
Therefore , option a is correct.