Concept:The anther is the male reproductive part of a flower that produces and releases pollen grains.
Explanation:A flower's male reproductive organ is the stamen.
The stamen has two main parts: the filament and the anther.
The filament is a thin stalk that holds the anther up.
The anther is the sac-like top part where pollen grains are formed.
Therefore, the specific part that produces pollen grains is the anther.
The petal is only a colourful leaf-like structure that attracts pollinators.
The stamen is the whole organ, not just the pollen-producing part.
Thus, among the given choices, the anther is the correct part.
Answer:D. anther